TabbedPane: replaced forward/backward scrolling arrow buttons with "Show Hidden Tabs" button (issue #40)

CHANGELOG.md

@@ -5,6 +5,11 @@ FlatLaf Change Log
 
 #### New features and improvements
 
+- TabbedPane: Replaced forward/backward scrolling arrow buttons with "Show
+  Hidden Tabs" button. If pressed, it shows a popup menu that contains (partly)
+  hidden tabs and selecting one activates that tab. If you prefer
+  forward/backward buttons, use `UIManager.put(
+  "TabbedPane.hiddenTabsNavigation", "arrowButtons" )`. (issue #40)
 - TabbedPane: Support scrolling tabs with mouse wheel (if `tabLayoutPolicy` is
   `SCROLL_TAB_LAYOUT`). (issue #40)
 - TabbedPane: Repeat scrolling as long as arrow buttons are pressed. (issue #40)

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatTabbedPaneUI.java

@@ -20,16 +20,23 @@ import static com.formdev.flatlaf.util.UIScale.scale;
 import static com.formdev.flatlaf.FlatClientProperties.*;
 import java.awt.Color;
 import java.awt.Component;
+import java.awt.Container;
 import java.awt.Dimension;
+import java.awt.EventQueue;
 import java.awt.Font;
 import java.awt.FontMetrics;
 import java.awt.Graphics;
 import java.awt.Graphics2D;
 import java.awt.Insets;
 import java.awt.KeyboardFocusManager;
+import java.awt.LayoutManager;
 import java.awt.Point;
 import java.awt.Rectangle;
 import java.awt.Shape;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+import java.awt.event.ComponentEvent;
+import java.awt.event.ComponentListener;
 import java.awt.event.InputEvent;
 import java.awt.event.KeyEvent;
 import java.awt.event.MouseAdapter;
@@ -41,15 +48,22 @@ import java.awt.geom.Rectangle2D;
 import java.beans.PropertyChangeEvent;
 import java.beans.PropertyChangeListener;
 import java.util.Collections;
+import java.util.Locale;
 import java.util.Set;
 import javax.swing.JButton;
 import javax.swing.JComponent;
+import javax.swing.JMenuItem;
+import javax.swing.JPopupMenu;
 import javax.swing.JTabbedPane;
 import javax.swing.JViewport;
 import javax.swing.KeyStroke;
 import javax.swing.SwingUtilities;
 import javax.swing.Timer;
 import javax.swing.UIManager;
+import javax.swing.event.ChangeEvent;
+import javax.swing.event.ChangeListener;
+import javax.swing.event.PopupMenuEvent;
+import javax.swing.event.PopupMenuListener;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.UIResource;
 import javax.swing.plaf.basic.BasicTabbedPaneUI;
@@ -100,6 +114,7 @@ import com.formdev.flatlaf.util.UIScale;
  * @uiDefault TabbedPane.showTabSeparators				boolean
  * @uiDefault TabbedPane.tabSeparatorsFullHeight		boolean
  * @uiDefault TabbedPane.hasFullBorder					boolean
+ * @uiDefault TabbedPane.hiddenTabsNavigation			String	moreTabsButton (default) or arrowButtons
  * @uiDefault ScrollPane.smoothScrolling				boolean
  *
  * @author Karl Tauber
@@ -107,6 +122,10 @@ import com.formdev.flatlaf.util.UIScale;
 public class FlatTabbedPaneUI
 	extends BasicTabbedPaneUI
 {
+	// hidden tabs navigation types
+	protected static final int MORE_TABS_BUTTON = 0;
+	protected static final int ARROW_BUTTONS = 1;
+
 	private static Set<KeyStroke> focusForwardTraversalKeys;
 	private static Set<KeyStroke> focusBackwardTraversalKeys;
 
@@ -128,9 +147,15 @@ public class FlatTabbedPaneUI
 	protected boolean hasFullBorder;
 	protected boolean tabsOverlapBorder;
 
+	protected int hiddenTabsNavigation = MORE_TABS_BUTTON;
+
+	protected String moreTabsButtonToolTipText;
+
 	protected JViewport tabViewport;
 	protected FlatWheelTabScroller wheelTabScroller;
 
+	private JButton moreTabsButton;
+
 	private Handler handler;
 	private boolean blockRollover;
 
@@ -140,7 +165,28 @@ public class FlatTabbedPaneUI
 
 	@Override
 	protected void installDefaults() {
-		super.installDefaults();
+		if( UIManager.getBoolean( "TabbedPane.tabsOverlapBorder" ) ) {
+			// Force BasicTabbedPaneUI.tabsOverlapBorder to false,
+			// which is necessary for "more tabs" button to work correctly.
+			//
+			// If it would be true, class TabbedPaneScrollLayout would invoke TabbedPaneLayout.padSelectedTab(),
+			// which would modify rectangle of selected tab in a wrong way (for wrap tab layout policy).
+			// This would cause tab painting issues when scrolled and
+			// missing "more tabs" button if last tab is selected.
+			//
+			// All methods of BasicTabbedPaneUI that use tabsOverlapBorder (except
+			// the one method mentioned above) are overridden.
+			//
+			// This is normally not invoked because the default value for
+			// TabbedPane.tabsOverlapBorder is false in all FlatLaf themes.
+			// Anyway, 3rd party themes may have changed it.
+			// So make sure that it works anyway to avoid issues.
+			Object oldValue = UIManager.put( "TabbedPane.tabsOverlapBorder", false );
+			super.installDefaults();
+			UIManager.put( "TabbedPane.tabsOverlapBorder", oldValue );
+		} else
+			super.installDefaults();
+
 
 		disabledForeground = UIManager.getColor( "TabbedPane.disabledForeground" );
 		selectedBackground = UIManager.getColor( "TabbedPane.selectedBackground" );
@@ -160,6 +206,9 @@ public class FlatTabbedPaneUI
 		hasFullBorder = UIManager.getBoolean( "TabbedPane.hasFullBorder" );
 		tabsOverlapBorder = UIManager.getBoolean( "TabbedPane.tabsOverlapBorder" );
 
+		Locale l = tabPane.getLocale();
+		moreTabsButtonToolTipText = UIManager.getString( "TabbedPane.moreTabsButtonToolTipText", l );
+
 		// scale
 		textIconGap = scale( textIconGap );
 		tabInsets = scale( tabInsets );
@@ -218,6 +267,47 @@ public class FlatTabbedPaneUI
 				}
 			}
 		}
+
+		// initialize here because used in installHiddenTabsNavigation() before installDefaults() was invoked
+		hiddenTabsNavigation = parseHiddenTabsNavigation( UIManager.getString( "TabbedPane.hiddenTabsNavigation" ) );
+
+		installHiddenTabsNavigation();
+	}
+
+	private void installHiddenTabsNavigation() {
+		if( hiddenTabsNavigation != MORE_TABS_BUTTON ||
+			!isScrollTabLayout() ||
+			tabViewport == null )
+		  return;
+
+		// At this point, BasicTabbedPaneUI already has installed
+		// TabbedPaneScrollLayout (in super.createLayoutManager()) and
+		// ScrollableTabSupport, ScrollableTabViewport, ScrollableTabPanel, etc
+		// (in super.installComponents()).
+
+		// install own layout manager that delegates to original layout manager
+		tabPane.setLayout( createScrollLayoutManager( (TabbedPaneLayout) tabPane.getLayout() ) );
+
+		// create and add "more tabs" button
+		moreTabsButton = createMoreTabsButton();
+		tabPane.add( moreTabsButton );
+	}
+
+	@Override
+	protected void uninstallComponents() {
+		// restore layout manager before invoking super.uninstallComponents() for
+		// correct uninstallation of BasicTabbedPaneUI tab scroller support
+		if( tabPane.getLayout() instanceof FlatTabbedPaneScrollLayout )
+			tabPane.setLayout( ((FlatTabbedPaneScrollLayout)tabPane.getLayout()).delegate );
+
+		super.uninstallComponents();
+
+		if( moreTabsButton != null ) {
+			tabPane.remove( moreTabsButton );
+			moreTabsButton = null;
+		}
+
+		tabViewport = null;
 	}
 
 	@Override
@@ -225,6 +315,8 @@ public class FlatTabbedPaneUI
 		super.installListeners();
 
 		tabPane.addMouseListener( getHandler() );
+		tabPane.addMouseMotionListener( getHandler() );
+		tabPane.addComponentListener( getHandler() );
 
 		if( tabViewport != null && (wheelTabScroller = createWheelTabScroller()) != null ) {
 			// ideally we would add the mouse listeners to the viewport, but then the
@@ -242,6 +334,8 @@ public class FlatTabbedPaneUI
 
 		if( handler != null ) {
 			tabPane.removeMouseListener( handler );
+			tabPane.removeMouseMotionListener( handler );
+			tabPane.removeComponentListener( handler );
 			handler = null;
 		}
 
@@ -272,6 +366,21 @@ public class FlatTabbedPaneUI
 		return handler;
 	}
 
+	@Override
+	protected ChangeListener createChangeListener() {
+		Handler handler = getHandler();
+		handler.changeDelegate = super.createChangeListener();
+		return handler;
+	}
+
+	protected LayoutManager createScrollLayoutManager( TabbedPaneLayout delegate ) {
+		return new FlatTabbedPaneScrollLayout( delegate );
+	}
+
+	protected JButton createMoreTabsButton() {
+		return new FlatMoreTabsButton();
+	}
+
 	@Override
 	protected JButton createScrollButton( int direction ) {
 		return new FlatScrollableTabButton( direction );
@@ -353,6 +462,19 @@ public class FlatTabbedPaneUI
 		super.update( g, c );
 	}
 
+	@Override
+	public void paint( Graphics g, JComponent c ) {
+		ensureCurrentLayout();
+
+		int tabPlacement = tabPane.getTabPlacement();
+		int selectedIndex = tabPane.getSelectedIndex();
+
+		paintContentBorder( g, tabPlacement, selectedIndex );
+
+		if( !isScrollTabLayout() )
+			paintTabArea( g, tabPlacement, selectedIndex );
+	}
+
 	@Override
 	protected void paintText( Graphics g, int tabPlacement, Font font, FontMetrics metrics,
 		int tabIndex, String title, Rectangle textRect, boolean isSelected )
@@ -573,6 +695,43 @@ public class FlatTabbedPaneUI
 	{
 	}
 
+	@Override
+	public int tabForCoordinate( JTabbedPane pane, int x, int y ) {
+		if( moreTabsButton != null ) {
+			// convert x,y from JTabbedPane coordinate space to ScrollableTabPanel coordinate space
+			Point viewPosition = tabViewport.getViewPosition();
+			x = x - tabViewport.getX() + viewPosition.x;
+			y = y - tabViewport.getY() + viewPosition.y;
+
+			// check whether point is within viewport
+			if( !tabViewport.getViewRect().contains( x, y ) )
+				return -1;
+		}
+
+		return super.tabForCoordinate( pane, x, y );
+	}
+
+	@Override
+	protected Rectangle getTabBounds( int tabIndex, Rectangle dest ) {
+		if( moreTabsButton != null ) {
+			// copy tab bounds to dest
+			dest.setBounds( rects[tabIndex] );
+
+			// convert tab bounds to coordinate space of JTabbedPane
+			Point viewPosition = tabViewport.getViewPosition();
+			dest.x = dest.x + tabViewport.getX() - viewPosition.x;
+			dest.y = dest.y + tabViewport.getY() - viewPosition.y;
+			return dest;
+		} else
+			return super.getTabBounds( tabIndex, dest );
+	}
+
+	protected void ensureCurrentLayout() {
+		// since super.ensureCurrentLayout() is private,
+		// use super.getTabRunCount() as workaround
+		super.getTabRunCount( tabPane );
+	}
+
 	private boolean isLastInRun( int tabIndex ) {
 		int run = getRunForTab( tabPane.getTabCount(), tabIndex );
 		return lastTabInRun( tabPane.getTabCount(), run ) == tabIndex;
@@ -592,6 +751,170 @@ public class FlatTabbedPaneUI
 		return UIManager.getBoolean( "ScrollPane.smoothScrolling" );
 	}
 
+	protected static int parseHiddenTabsNavigation( String str ) {
+		if( str == null )
+			return MORE_TABS_BUTTON;
+
+		switch( str ) {
+			default:
+			case "moreTabsButton":	return MORE_TABS_BUTTON;
+			case "arrowButtons":	return ARROW_BUTTONS;
+		}
+	}
+
+	private void runWithOriginalLayoutManager( Runnable runnable ) {
+		LayoutManager layout = tabPane.getLayout();
+		if( layout instanceof FlatTabbedPaneScrollLayout ) {
+			// temporary change layout manager because the runnable may use
+			// BasicTabbedPaneUI.scrollableTabLayoutEnabled()
+			tabPane.setLayout( ((FlatTabbedPaneScrollLayout)layout).delegate );
+			runnable.run();
+			tabPane.setLayout( layout );
+		} else
+			runnable.run();
+	}
+
+	protected void ensureSelectedTabIsVisible() {
+		if( tabPane == null || tabViewport == null )
+			return;
+
+		int selectedIndex = tabPane.getSelectedIndex();
+		if( selectedIndex < 0 )
+			return;
+
+		Rectangle tabBounds = getTabBounds( tabPane, selectedIndex );
+		tabViewport.scrollRectToVisible( tabBounds );
+	}
+
+	//---- class FlatMoreTabsButton -------------------------------------------
+
+	protected class FlatMoreTabsButton
+		extends FlatArrowButton
+		implements ActionListener, PopupMenuListener
+	{
+		private boolean popupVisible;
+
+		public FlatMoreTabsButton() {
+			// this method is invoked before installDefaults(), so we can not use color fields here
+			super( SOUTH, UIManager.getString( "Component.arrowType" ),
+				UIManager.getColor( "TabbedPane.foreground" ),
+				UIManager.getColor( "TabbedPane.disabledForeground" ), null,
+				UIManager.getColor( "TabbedPane.hoverColor" ) );
+
+			updateDirection();
+			setToolTipText( moreTabsButtonToolTipText );
+			addActionListener( this );
+		}
+
+		protected void updateDirection() {
+			int direction;
+			switch( tabPane.getTabPlacement() ) {
+				default:
+				case TOP:	direction = SOUTH; break;
+				case BOTTOM:	direction = NORTH; break;
+				case LEFT:	direction = EAST; break;
+				case RIGHT:	direction = WEST; break;
+
+			}
+			setDirection( direction );
+		}
+
+		@Override
+		public void paint( Graphics g ) {
+			// paint arrow button near separator line
+			if( direction == EAST || direction == WEST ) {
+				int xoffset = (getWidth() / 2) - getHeight();
+				setXOffset( (direction == EAST) ? xoffset : -xoffset );
+			}
+
+			super.paint( g );
+		}
+
+		@Override
+		protected boolean isHover() {
+			return super.isHover() || popupVisible;
+		}
+
+		@Override
+		public void actionPerformed( ActionEvent e ) {
+			if( tabViewport == null )
+				return;
+
+			// detect (partly) hidden tabs and build popup menu
+			JPopupMenu popupMenu = new JPopupMenu();
+			popupMenu.addPopupMenuListener( this );
+			Rectangle viewRect = tabViewport.getViewRect();
+			int lastIndex = -1;
+			for( int i = 0; i < rects.length; i++ ) {
+				if( !viewRect.contains( rects[i] ) ) {
+					// add separator between leading and trailing tabs
+					if( lastIndex >= 0 && lastIndex + 1 != i )
+						popupMenu.addSeparator();
+					lastIndex = i;
+
+					// create menu item for tab
+					popupMenu.add( createMenuItem( i ) );
+				}
+			}
+
+			// show popup menu
+			int buttonWidth = getWidth();
+			int buttonHeight = getHeight();
+			int x = 0;
+			int y = 0;
+			Dimension popupSize = popupMenu.getPreferredSize();
+			switch( tabPane.getTabPlacement() ) {
+				default:
+				case TOP:	x = buttonWidth - popupSize.width; y = buttonHeight; break;
+				case BOTTOM:	x = buttonWidth - popupSize.width; y = -popupSize.height; break;
+				case LEFT:	x = buttonWidth; y = buttonHeight - popupSize.height; break;
+				case RIGHT:	x = -popupSize.width; y = buttonHeight - popupSize.height; break;
+
+			}
+			popupMenu.show( this, x, y );
+		}
+
+		protected JMenuItem createMenuItem( int index ) {
+			JMenuItem menuItem = new JMenuItem( tabPane.getTitleAt( index ), tabPane.getIconAt( index ) );
+			menuItem.setDisabledIcon( tabPane.getDisabledIconAt( index ) );
+			menuItem.setToolTipText( tabPane.getToolTipTextAt( index ) );
+
+			Color foregroundAt = tabPane.getForegroundAt( index );
+			if( foregroundAt != tabPane.getForeground() )
+				menuItem.setForeground( foregroundAt );
+
+			Color backgroundAt = tabPane.getBackgroundAt( index );
+			if( backgroundAt != tabPane.getBackground() ) {
+				menuItem.setBackground( backgroundAt );
+				menuItem.setOpaque( true );
+			}
+
+			if( !tabPane.isEnabledAt( index ) )
+				menuItem.setEnabled( false );
+
+			menuItem.addActionListener( e -> tabPane.setSelectedIndex( index ) );
+			return menuItem;
+		}
+
+		@Override
+		public void popupMenuWillBecomeVisible( PopupMenuEvent e ) {
+			popupVisible = true;
+			repaint();
+		}
+
+		@Override
+		public void popupMenuWillBecomeInvisible( PopupMenuEvent e ) {
+			popupVisible = false;
+			repaint();
+		}
+
+		@Override
+		public void popupMenuCanceled( PopupMenuEvent e ) {
+			popupVisible = false;
+			repaint();
+		}
+	}
+
 	//---- class FlatScrollableTabButton --------------------------------------
 
 	protected class FlatScrollableTabButton
@@ -612,11 +935,21 @@ public class FlatTabbedPaneUI
 
 		@Override
 		public Dimension getPreferredSize() {
+			// Use half width/height if "more tabs" button is used, because size of
+			// "more tabs" button is the union of the backward and forward scroll buttons.
+			// With this "trick", viewport gets correct size.
+			boolean halfSize = (hiddenTabsNavigation == MORE_TABS_BUTTON);
+
 			Dimension size = super.getPreferredSize();
-			if( direction == WEST || direction == EAST )
-				return new Dimension( size.width, Math.max( size.height, maxTabHeight ) );
-			else
-				return new Dimension( Math.max( size.width, maxTabWidth ), size.height );
+			if( direction == WEST || direction == EAST ) {
+				return new Dimension(
+					halfSize ? ((size.width / 2) + scale( 4 )) : size.width,
+					Math.max( size.height, maxTabHeight ) );
+			} else {
+				return new Dimension(
+					Math.max( size.width, maxTabWidth ),
+					halfSize ? ((size.height / 2) + scale( 4 )) : size.height );
+			}
 		}
 
 		@Override
@@ -871,11 +1204,8 @@ public class FlatTabbedPaneUI
 				return;
 			scrolled = false;
 
-			int selectedIndex = tabPane.getSelectedIndex();
-			if( selectedIndex >= 0 ) {
-				Rectangle tabBounds = getTabBounds( tabPane, selectedIndex );
-				tabViewport.scrollRectToVisible( tabBounds );
-			}
+			// scroll selected tab into visible area
+			ensureSelectedTabIsVisible();
 		}
 	}
 
@@ -883,9 +1213,18 @@ public class FlatTabbedPaneUI
 
 	private class Handler
 		extends MouseAdapter
-		implements PropertyChangeListener
+		implements PropertyChangeListener, ChangeListener, ComponentListener
 	{
 		PropertyChangeListener propertyChangeDelegate;
+		ChangeListener changeDelegate;
+
+		//---- interface MouseListener ----
+
+		@Override
+		public void mouseEntered( MouseEvent e ) {
+			// this is necessary for "more tabs" button
+			setRolloverTab( e.getX(), e.getY() );
+		}
 
 		@Override
 		public void mouseExited( MouseEvent e ) {
@@ -895,11 +1234,41 @@ public class FlatTabbedPaneUI
 			setRolloverTab( e.getX(), e.getY() );
 		}
 
+		//---- interface MouseMotionListener ----
+
+		@Override
+		public void mouseMoved( MouseEvent e ) {
+			// this is necessary for "more tabs" button
+			setRolloverTab( e.getX(), e.getY() );
+		}
+
+		//---- interface PropertyChangeListener ----
+
 		@Override
 		public void propertyChange( PropertyChangeEvent e ) {
-			propertyChangeDelegate.propertyChange( e );
-
+			// invoke delegate listener
 			switch( e.getPropertyName() ) {
+				case "tabPlacement":
+				case "opaque":
+				case "background":
+				case "indexForTabComponent":
+					runWithOriginalLayoutManager( () -> {
+						propertyChangeDelegate.propertyChange( e );
+					} );
+					break;
+
+				default:
+					propertyChangeDelegate.propertyChange( e );
+					break;
+			}
+
+			// handle event
+			switch( e.getPropertyName() ) {
+				case "tabPlacement":
+					if( moreTabsButton instanceof FlatMoreTabsButton )
+						((FlatMoreTabsButton)moreTabsButton).updateDirection();
+					break;
+
 				case TABBED_PANE_SHOW_TAB_SEPARATORS:
 				case TABBED_PANE_SHOW_CONTENT_SEPARATOR:
 				case TABBED_PANE_HAS_FULL_BORDER:
@@ -909,5 +1278,112 @@ public class FlatTabbedPaneUI
 					break;
 			}
 		}
+
+		//---- interface ChangeListener ----
+
+		@Override
+		public void stateChanged( ChangeEvent e ) {
+			changeDelegate.stateChanged( e );
+
+			// scroll selected tab into visible area
+			if( moreTabsButton != null )
+				ensureSelectedTabIsVisible();
+		}
+
+		//---- interface ComponentListener ----
+
+		@Override
+		public void componentResized( ComponentEvent e ) {
+			// make sure that selected tab stays visible when component size changed
+			EventQueue.invokeLater( () -> {
+				ensureSelectedTabIsVisible();
+			} );
+		}
+
+		@Override public void componentMoved( ComponentEvent e ) {}
+		@Override public void componentShown( ComponentEvent e ) {}
+		@Override public void componentHidden( ComponentEvent e ) {}
+	}
+
+	//---- class FlatTabbedPaneScrollLayout -----------------------------------
+
+	/**
+	 * Layout manager used if "TabbedPane.hiddenTabsNavigation" is "moreTabsButton".
+	 * <p>
+	 * Although this class delegates all methods to the original layout manager
+	 * {@link BasicTabbedPaneUI.TabbedPaneScrollLayout}, which extends
+	 * {@link BasicTabbedPaneUI.TabbedPaneLayout}, it is necessary that this class
+	 * also extends {@link TabbedPaneLayout} to avoid a {@code ClassCastException}
+	 * in {@link BasicTabbedPaneUI}.ensureCurrentLayout().
+	 */
+	protected class FlatTabbedPaneScrollLayout
+		extends TabbedPaneLayout
+		implements LayoutManager
+	{
+		private final TabbedPaneLayout delegate;
+
+		protected FlatTabbedPaneScrollLayout( TabbedPaneLayout delegate ) {
+			this.delegate = delegate;
+		}
+
+		@Override
+		public void calculateLayoutInfo() {
+			delegate.calculateLayoutInfo();
+		}
+
+		//---- interface LayoutManager ----
+
+		@Override
+		public void addLayoutComponent( String name, Component comp ) {
+			delegate.addLayoutComponent( name, comp );
+		}
+
+		@Override
+		public void removeLayoutComponent( Component comp ) {
+			delegate.removeLayoutComponent( comp );
+		}
+
+		@Override
+		public Dimension preferredLayoutSize( Container parent ) {
+			return delegate.preferredLayoutSize( parent );
+		}
+
+		@Override
+		public Dimension minimumLayoutSize( Container parent ) {
+			return delegate.minimumLayoutSize( parent );
+		}
+
+		@Override
+		public void layoutContainer( Container parent ) {
+			// delegate to original layout manager and let it layout tabs and buttons
+			//
+			// runWithOriginalLayoutManager() is necessary for correct locations
+			// of tab components layed out in TabbedPaneLayout.layoutTabComponents()
+			runWithOriginalLayoutManager( () -> {
+				delegate.layoutContainer( parent );
+			} );
+
+			// check whether scroll buttons are visible, which is changed by original
+			// layout manager depending on whether there is enough room for all tabs
+			boolean scrollButtonsVisible = false;
+			Rectangle buttonsBounds = null;
+			for( Component c : tabPane.getComponents() ) {
+				if( c instanceof FlatScrollableTabButton && c.isVisible() ) {
+					scrollButtonsVisible = true;
+
+					// compute union bounds of all scroll buttons
+					Rectangle r = c.getBounds();
+					buttonsBounds = (buttonsBounds != null) ? buttonsBounds.union( r ) : r;
+
+					// hide scroll button
+					c.setVisible( false );
+				}
+			}
+
+			// show/hide "more tabs" button and layout it
+			moreTabsButton.setVisible( scrollButtonsVisible );
+			if( buttonsBounds != null )
+				moreTabsButton.setBounds( buttonsBounds );
+		}
 	}
 }

flatlaf-core/src/main/resources/com/formdev/flatlaf/FlatLaf.properties

@@ -546,10 +546,11 @@ TabbedPane.tabInsets=4,12,4,12
 TabbedPane.tabAreaInsets=0,0,0,0
 TabbedPane.selectedTabPadInsets=0,0,0,0
 TabbedPane.tabRunOverlay=0
-TabbedPane.tabsOverlapBorder=true
+TabbedPane.tabsOverlapBorder=false
 TabbedPane.disabledForeground=@disabledText
 TabbedPane.shadow=@background
 TabbedPane.contentBorderInsets=null
+TabbedPane.hiddenTabsNavigation=moreTabsButton
 
 
 #---- Table ----

flatlaf-core/src/main/resources/com/formdev/flatlaf/resources/Bundle.properties

@@ -46,3 +46,8 @@ FileChooser.refreshActionLabelText=Refresh
 FileChooser.newFolderActionLabelText=New Folder
 FileChooser.listViewActionLabelText=List
 FileChooser.detailsViewActionLabelText=Details
+
+
+#---- TabbedPane ----
+
+TabbedPane.moreTabsButtonToolTipText=Show Hidden Tabs

flatlaf-core/src/main/resources/com/formdev/flatlaf/resources/Bundle_de.properties

@@ -46,3 +46,8 @@ FileChooser.refreshActionLabelText=Aktualisieren
 FileChooser.newFolderActionLabelText=Neuer Ordner
 FileChooser.listViewActionLabelText=Liste
 FileChooser.detailsViewActionLabelText=Details
+
+
+#---- TabbedPane ----
+
+TabbedPane.moreTabsButtonToolTipText=Verdeckte Tabs anzeigen

flatlaf-testing/dumps/uidefaults/FlatDarkLaf_1.8.0_202.txt

@@ -916,6 +916,7 @@ TabbedPane.focusColor          #3d4b5c    javax.swing.plaf.ColorUIResource [UI]
 TabbedPane.font                [active] $defaultFont [UI]
 TabbedPane.foreground          #bbbbbb    javax.swing.plaf.ColorUIResource [UI]
 TabbedPane.hasFullBorder       false
+TabbedPane.hiddenTabsNavigation moreTabsButton
 TabbedPane.highlight           #242424    javax.swing.plaf.ColorUIResource [UI]
 TabbedPane.hoverColor          #2e3133    javax.swing.plaf.ColorUIResource [UI]
 TabbedPane.labelShift          1
@@ -932,7 +933,7 @@ TabbedPane.tabRunOverlay       0
 TabbedPane.tabSelectionHeight  3
 TabbedPane.tabSeparatorsFullHeight false
 TabbedPane.tabsOpaque          true
-TabbedPane.tabsOverlapBorder   true
+TabbedPane.tabsOverlapBorder   false
 TabbedPane.textIconGap         4
 TabbedPane.underlineColor      #4a88c7    javax.swing.plaf.ColorUIResource [UI]
 TabbedPaneUI                   com.formdev.flatlaf.ui.FlatTabbedPaneUI

flatlaf-testing/dumps/uidefaults/FlatLightLaf_1.8.0_202.txt

@@ -921,6 +921,7 @@ TabbedPane.focusColor          #dae4ed    javax.swing.plaf.ColorUIResource [UI]
 TabbedPane.font                [active] $defaultFont [UI]
 TabbedPane.foreground          #000000    javax.swing.plaf.ColorUIResource [UI]
 TabbedPane.hasFullBorder       false
+TabbedPane.hiddenTabsNavigation moreTabsButton
 TabbedPane.highlight           #ffffff    javax.swing.plaf.ColorUIResource [UI]
 TabbedPane.hoverColor          #d9d9d9    javax.swing.plaf.ColorUIResource [UI]
 TabbedPane.labelShift          1
@@ -937,7 +938,7 @@ TabbedPane.tabRunOverlay       0
 TabbedPane.tabSelectionHeight  3
 TabbedPane.tabSeparatorsFullHeight false
 TabbedPane.tabsOpaque          true
-TabbedPane.tabsOverlapBorder   true
+TabbedPane.tabsOverlapBorder   false
 TabbedPane.textIconGap         4
 TabbedPane.underlineColor      #4083c9    javax.swing.plaf.ColorUIResource [UI]
 TabbedPaneUI                   com.formdev.flatlaf.ui.FlatTabbedPaneUI

flatlaf-testing/dumps/uidefaults/FlatTestLaf_1.8.0_202.txt

@@ -909,6 +909,7 @@ TabbedPane.focusColor          #dddddd    javax.swing.plaf.ColorUIResource [UI]
 TabbedPane.font                [active] $defaultFont [UI]
 TabbedPane.foreground          #ff0000    javax.swing.plaf.ColorUIResource [UI]
 TabbedPane.hasFullBorder       false
+TabbedPane.hiddenTabsNavigation moreTabsButton
 TabbedPane.highlight           #ffffff    javax.swing.plaf.ColorUIResource [UI]
 TabbedPane.hoverColor          #eeeeee    javax.swing.plaf.ColorUIResource [UI]
 TabbedPane.labelShift          1
@@ -928,7 +929,7 @@ TabbedPane.tabSelectionHeight  3
 TabbedPane.tabSeparatorColor   #0000ff    javax.swing.plaf.ColorUIResource [UI]
 TabbedPane.tabSeparatorsFullHeight false
 TabbedPane.tabsOpaque          true
-TabbedPane.tabsOverlapBorder   true
+TabbedPane.tabsOverlapBorder   false
 TabbedPane.textIconGap         4
 TabbedPane.underlineColor      #4a88c7    javax.swing.plaf.ColorUIResource [UI]
 TabbedPaneUI                   com.formdev.flatlaf.ui.FlatTabbedPaneUI

flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/FlatContainerTest.java

@@ -215,6 +215,27 @@ public class FlatContainerTest
 		return tab;
 	}
 
+	private void tabPlacementChanged() {
+		int tabPlacement = -1;
+		switch( (String) tabPlacementField.getSelectedItem() ) {
+			case "top":		tabPlacement = SwingConstants.TOP; break;
+			case "bottom":	tabPlacement = SwingConstants.BOTTOM; break;
+			case "left":	tabPlacement = SwingConstants.LEFT; break;
+			case "right":	tabPlacement = SwingConstants.RIGHT; break;
+		}
+
+		tabbedPane1.setTabPlacement( (tabPlacement >= 0) ? tabPlacement : SwingConstants.TOP );
+		tabbedPane2.setTabPlacement( (tabPlacement >= 0) ? tabPlacement : SwingConstants.BOTTOM );
+		tabbedPane3.setTabPlacement( (tabPlacement >= 0) ? tabPlacement : SwingConstants.LEFT );
+		tabbedPane4.setTabPlacement( (tabPlacement >= 0) ? tabPlacement : SwingConstants.RIGHT );
+	}
+
+	private void tabBackForegroundChanged() {
+		boolean enabled = tabBackForegroundCheckBox.isSelected();
+		tabbedPane1.setBackgroundAt( 0, enabled ? Color.red : null );
+		tabbedPane1.setForegroundAt( 1, enabled ? Color.red : null );
+	}
+
 	private void initComponents() {
 		// JFormDesigner - Component initialization - DO NOT MODIFY  //GEN-BEGIN:initComponents
 		JPanel panel9 = new JPanel();
@@ -244,6 +265,9 @@ public class FlatContainerTest
 		customBorderCheckBox = new JCheckBox();
 		customTabsCheckBox = new JCheckBox();
 		hasFullBorderCheckBox = new JCheckBox();
+		JLabel tabPlacementLabel = new JLabel();
+		tabPlacementField = new JComboBox<>();
+		tabBackForegroundCheckBox = new JCheckBox();
 		CellConstraints cc = new CellConstraints();
 
 		//======== this ========
@@ -356,6 +380,7 @@ public class FlatContainerTest
 					"[fill]",
 					// rows
 					"[center]" +
+					"[]" +
 					"[]"));
 
 				//---- moreTabsCheckBox ----
@@ -411,6 +436,26 @@ public class FlatContainerTest
 				hasFullBorderCheckBox.setText("Show content border");
 				hasFullBorderCheckBox.addActionListener(e -> hasFullBorderChanged());
 				panel14.add(hasFullBorderCheckBox, "cell 4 1,alignx left,growx 0");
+
+				//---- tabPlacementLabel ----
+				tabPlacementLabel.setText("Tab placement:");
+				panel14.add(tabPlacementLabel, "cell 0 2");
+
+				//---- tabPlacementField ----
+				tabPlacementField.setModel(new DefaultComboBoxModel<>(new String[] {
+					"default",
+					"top",
+					"bottom",
+					"left",
+					"right"
+				}));
+				tabPlacementField.addActionListener(e -> tabPlacementChanged());
+				panel14.add(tabPlacementField, "cell 1 2");
+
+				//---- tabBackForegroundCheckBox ----
+				tabBackForegroundCheckBox.setText("Tab back/foreground");
+				tabBackForegroundCheckBox.addActionListener(e -> tabBackForegroundChanged());
+				panel14.add(tabBackForegroundCheckBox, "cell 4 2");
 			}
 			panel9.add(panel14, cc.xywh(1, 11, 3, 1));
 		}
@@ -433,6 +478,8 @@ public class FlatContainerTest
 	private JCheckBox customBorderCheckBox;
 	private JCheckBox customTabsCheckBox;
 	private JCheckBox hasFullBorderCheckBox;
+	private JComboBox<String> tabPlacementField;
+	private JCheckBox tabBackForegroundCheckBox;
 	// JFormDesigner - End of variables declaration  //GEN-END:variables
 
 	//---- class Tab1Panel ----------------------------------------------------

flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/FlatContainerTest.jfd

@@ -132,7 +132,7 @@ new FormModel {
 				add( new FormContainer( "javax.swing.JPanel", new FormLayoutManager( class net.miginfocom.swing.MigLayout ) {
 					"$layoutConstraints": "insets 0,hidemode 3"
 					"$columnConstraints": "[][fill][][][fill]"
-					"$rowConstraints": "[center][]"
+					"$rowConstraints": "[center][][]"
 				} ) {
 					name: "panel14"
 					"opaque": false
@@ -251,6 +251,40 @@ new FormModel {
 					}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
 						"value": "cell 4 1,alignx left,growx 0"
 					} )
+					add( new FormComponent( "javax.swing.JLabel" ) {
+						name: "tabPlacementLabel"
+						"text": "Tab placement:"
+					}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+						"value": "cell 0 2"
+					} )
+					add( new FormComponent( "javax.swing.JComboBox" ) {
+						name: "tabPlacementField"
+						"model": new javax.swing.DefaultComboBoxModel {
+							selectedItem: "default"
+							addElement( "default" )
+							addElement( "top" )
+							addElement( "bottom" )
+							addElement( "left" )
+							addElement( "right" )
+						}
+						auxiliary() {
+							"JavaCodeGenerator.variableLocal": false
+							"JavaCodeGenerator.typeParameters": "String"
+						}
+						addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "tabPlacementChanged", false ) )
+					}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+						"value": "cell 1 2"
+					} )
+					add( new FormComponent( "javax.swing.JCheckBox" ) {
+						name: "tabBackForegroundCheckBox"
+						"text": "Tab back/foreground"
+						auxiliary() {
+							"JavaCodeGenerator.variableLocal": false
+						}
+						addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "tabBackForegroundChanged", false ) )
+					}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+						"value": "cell 4 2"
+					} )
 				}, new FormLayoutConstraints( class com.jgoodies.forms.layout.CellConstraints ) {
 					"gridY": 11
 					"gridWidth": 3
@@ -260,7 +294,7 @@ new FormModel {
 			} )
 		}, new FormLayoutConstraints( null ) {
 			"location": new java.awt.Point( 0, 0 )
-			"size": new java.awt.Dimension( 810, 515 )
+			"size": new java.awt.Dimension( 810, 570 )
 		} )
 		add( new FormContainer( "javax.swing.JPanel", new FormLayoutManager( class net.miginfocom.swing.MigLayout ) {
 			"$layoutConstraints": "hidemode 3,align center center"

flatlaf-theme-editor/src/main/resources/com/formdev/flatlaf/themeeditor/FlatLafUIKeys.txt

@@ -646,6 +646,7 @@ TabbedPane.focusInputMap
 TabbedPane.font
 TabbedPane.foreground
 TabbedPane.hasFullBorder
+TabbedPane.hiddenTabsNavigation
 TabbedPane.highlight
 TabbedPane.hoverColor
 TabbedPane.labelShift