List, Table and Tree: added colors for drag-and-drop

- added "enable drag and drop" checkbox to Demo on "Data Components" tab
- support copying UI default values lazy

flatlaf-demo/src/main/java/com/formdev/flatlaf/demo/DataComponentsPanel.java

@@ -16,6 +16,9 @@
 
 package com.formdev.flatlaf.demo;
 
+import java.awt.datatransfer.DataFlavor;
+import java.awt.datatransfer.StringSelection;
+import java.awt.datatransfer.Transferable;
 import javax.swing.*;
 import javax.swing.table.*;
 import net.miginfocom.swing.*;
@@ -30,22 +33,53 @@ class DataComponentsPanel
 		initComponents();
 	}
 
+	private void dndChanged() {
+		boolean dnd = dndCheckBox.isSelected();
+		list1.setDragEnabled( dnd );
+		list2.setDragEnabled( dnd );
+		tree1.setDragEnabled( dnd );
+		tree2.setDragEnabled( dnd );
+		table1.setDragEnabled( dnd );
+
+		DropMode dropMode = dnd ? DropMode.ON_OR_INSERT : DropMode.USE_SELECTION;
+		list1.setDropMode( dropMode );
+		tree1.setDropMode( dropMode );
+		table1.setDropMode( dropMode );
+
+		String key = "FlatLaf.oldTransferHandler";
+		if( dnd ) {
+			list1.putClientProperty( key, list1.getTransferHandler() );
+			list1.setTransferHandler( new DummyTransferHandler() );
+
+			tree1.putClientProperty( key, tree1.getTransferHandler() );
+			tree1.setTransferHandler( new DummyTransferHandler() );
+
+			table1.putClientProperty( key, table1.getTransferHandler() );
+			table1.setTransferHandler( new DummyTransferHandler() );
+		} else {
+			list1.setTransferHandler( (TransferHandler) list1.getClientProperty( key ) );
+			tree1.setTransferHandler( (TransferHandler) tree1.getClientProperty( key ) );
+			table1.setTransferHandler( (TransferHandler) table1.getClientProperty( key ) );
+		}
+	}
+
 	@SuppressWarnings( { "unchecked", "rawtypes" } )
 	private void initComponents() {
 		// JFormDesigner - Component initialization - DO NOT MODIFY  //GEN-BEGIN:initComponents
 		JLabel listLabel = new JLabel();
 		JScrollPane scrollPane1 = new JScrollPane();
-		JList<String> list1 = new JList<>();
+		list1 = new JList<>();
 		JScrollPane scrollPane2 = new JScrollPane();
-		JList<String> list2 = new JList<>();
+		list2 = new JList<>();
 		JLabel treeLabel = new JLabel();
 		JScrollPane scrollPane3 = new JScrollPane();
-		JTree tree1 = new JTree();
+		tree1 = new JTree();
 		JScrollPane scrollPane4 = new JScrollPane();
-		JTree tree2 = new JTree();
+		tree2 = new JTree();
 		JLabel tableLabel = new JLabel();
 		JScrollPane scrollPane5 = new JScrollPane();
-		JTable table1 = new JTable();
+		table1 = new JTable();
+		dndCheckBox = new JCheckBox();
 
 		//======== this ========
 		setLayout(new MigLayout(
@@ -57,7 +91,8 @@ class DataComponentsPanel
 			// rows
 			"[]" +
 			"[::200]" +
-			"[::150]"));
+			"[::150]" +
+			"[]"));
 
 		//---- listLabel ----
 		listLabel.setText("JList:");
@@ -65,15 +100,25 @@ class DataComponentsPanel
 
 		//======== scrollPane1 ========
 		{
-			scrollPane1.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_NEVER);
-			scrollPane1.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
 
 			//---- list1 ----
 			list1.setModel(new AbstractListModel<String>() {
 				String[] values = {
-					"abc",
-					"de",
-					"f"
+					"item 1",
+					"item 2",
+					"item 3",
+					"item 4",
+					"item 5",
+					"item 6",
+					"item 7",
+					"item 8",
+					"item 9",
+					"item 10",
+					"item 11",
+					"item 12",
+					"item 13",
+					"item 14",
+					"item 15"
 				};
 				@Override
 				public int getSize() { return values.length; }
@@ -86,15 +131,25 @@ class DataComponentsPanel
 
 		//======== scrollPane2 ========
 		{
-			scrollPane2.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_NEVER);
-			scrollPane2.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
 
 			//---- list2 ----
 			list2.setModel(new AbstractListModel<String>() {
 				String[] values = {
-					"abc",
-					"de",
-					"f"
+					"item 1",
+					"item 2",
+					"item 3",
+					"item 4",
+					"item 5",
+					"item 6",
+					"item 7",
+					"item 8",
+					"item 9",
+					"item 10",
+					"item 11",
+					"item 12",
+					"item 13",
+					"item 14",
+					"item 15"
 				};
 				@Override
 				public int getSize() { return values.length; }
@@ -115,6 +170,7 @@ class DataComponentsPanel
 
 			//---- tree1 ----
 			tree1.setShowsRootHandles(true);
+			tree1.setEditable(true);
 			scrollPane3.setViewportView(tree1);
 		}
 		add(scrollPane3, "cell 1 1,growx");
@@ -138,8 +194,18 @@ class DataComponentsPanel
 			//---- table1 ----
 			table1.setModel(new DefaultTableModel(
 				new Object[][] {
-					{"Item 1a", "Item 2a", "January", "July", 123, null},
-					{"Item 1b", "Item 2b", "February", "August", 456, true},
+					{"item 1", "item 1b", "January", "July", 123, null},
+					{"item 2", "item 2b", "February", "August", 456, true},
+					{"item 3", null, "March", null, null, null},
+					{"item 4", null, "April", null, null, null},
+					{"item 5", null, "May", null, null, null},
+					{"item 6", null, "June", null, null, null},
+					{"item 7", null, "July", null, null, null},
+					{"item 8", null, "August", null, null, null},
+					{"item 9", null, "September", null, null, null},
+					{"item 10", null, "October", null, null, null},
+					{"item 11", null, "November", null, null, null},
+					{"item 12", null, "December", null, null, null},
 				},
 				new String[] {
 					"Not editable", "Text", "Combo", "Combo Editable", "Integer", "Boolean"
@@ -197,11 +263,60 @@ class DataComponentsPanel
 			scrollPane5.setViewportView(table1);
 		}
 		add(scrollPane5, "cell 1 2 2 1,growx,width 300");
+
+		//---- dndCheckBox ----
+		dndCheckBox.setText("enable drag and drop");
+		dndCheckBox.setMnemonic('D');
+		dndCheckBox.addActionListener(e -> dndChanged());
+		add(dndCheckBox, "cell 0 3 3 1");
 		// JFormDesigner - End of component initialization  //GEN-END:initComponents
 
 		((JComboBox)((DefaultCellEditor)table1.getColumnModel().getColumn( 3 ).getCellEditor()).getComponent()).setEditable( true );
 	}
 
 	// JFormDesigner - Variables declaration - DO NOT MODIFY  //GEN-BEGIN:variables
+	private JList<String> list1;
+	private JList<String> list2;
+	private JTree tree1;
+	private JTree tree2;
+	private JTable table1;
+	private JCheckBox dndCheckBox;
 	// JFormDesigner - End of variables declaration  //GEN-END:variables
+
+	//---- class DummyTransferHandler -----------------------------------------
+
+	private static class DummyTransferHandler
+		extends TransferHandler
+	{
+		@Override
+		protected Transferable createTransferable( JComponent c ) {
+			if( c instanceof JList && ((JList<?>)c).isSelectionEmpty() )
+				return null;
+			if( c instanceof JTree && ((JTree)c).isSelectionEmpty() )
+				return null;
+			if( c instanceof JTable && ((JTable)c).getSelectionModel().isSelectionEmpty() )
+				return null;
+
+			return new StringSelection( "dummy" );
+		}
+
+		@Override
+		public int getSourceActions( JComponent c ) {
+			return COPY;
+		}
+
+		@Override
+		public boolean canImport( TransferSupport support ) {
+			return support.isDataFlavorSupported( DataFlavor.stringFlavor );
+		}
+
+		@Override
+		public boolean importData( TransferSupport support ) {
+			String message = String.valueOf( support.getDropLocation() );
+			SwingUtilities.invokeLater( () -> {
+				JOptionPane.showMessageDialog( null, message, "Drop", JOptionPane.PLAIN_MESSAGE );
+			} );
+			return false;
+		}
+	}
 }

flatlaf-demo/src/main/java/com/formdev/flatlaf/demo/DataComponentsPanel.jfd

@@ -9,7 +9,7 @@ new FormModel {
 		add( new FormContainer( "javax.swing.JPanel", new FormLayoutManager( class net.miginfocom.swing.MigLayout ) {
 			"$layoutConstraints": "hidemode 3"
 			"$columnConstraints": "[][200][200]"
-			"$rowConstraints": "[][::200][::150]"
+			"$rowConstraints": "[][::200][::150][]"
 		} ) {
 			name: "this"
 			add( new FormComponent( "javax.swing.JLabel" ) {
@@ -20,17 +20,28 @@ new FormModel {
 			} )
 			add( new FormContainer( "javax.swing.JScrollPane", new FormLayoutManager( class javax.swing.JScrollPane ) ) {
 				name: "scrollPane1"
-				"verticalScrollBarPolicy": 21
-				"horizontalScrollBarPolicy": 31
 				add( new FormComponent( "javax.swing.JList" ) {
 					name: "list1"
-					"model": &DefaultListModel0 new javax.swing.DefaultListModel {
-						addElement( "abc" )
-						addElement( "de" )
-						addElement( "f" )
+					"model": new javax.swing.DefaultListModel {
+						addElement( "item 1" )
+						addElement( "item 2" )
+						addElement( "item 3" )
+						addElement( "item 4" )
+						addElement( "item 5" )
+						addElement( "item 6" )
+						addElement( "item 7" )
+						addElement( "item 8" )
+						addElement( "item 9" )
+						addElement( "item 10" )
+						addElement( "item 11" )
+						addElement( "item 12" )
+						addElement( "item 13" )
+						addElement( "item 14" )
+						addElement( "item 15" )
 					}
 					auxiliary() {
 						"JavaCodeGenerator.typeParameters": "String"
+						"JavaCodeGenerator.variableLocal": false
 					}
 				} )
 			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
@@ -38,14 +49,29 @@ new FormModel {
 			} )
 			add( new FormContainer( "javax.swing.JScrollPane", new FormLayoutManager( class javax.swing.JScrollPane ) ) {
 				name: "scrollPane2"
-				"verticalScrollBarPolicy": 21
-				"horizontalScrollBarPolicy": 31
 				add( new FormComponent( "javax.swing.JList" ) {
 					name: "list2"
-					"model": #DefaultListModel0
+					"model": new javax.swing.DefaultListModel {
+						addElement( "item 1" )
+						addElement( "item 2" )
+						addElement( "item 3" )
+						addElement( "item 4" )
+						addElement( "item 5" )
+						addElement( "item 6" )
+						addElement( "item 7" )
+						addElement( "item 8" )
+						addElement( "item 9" )
+						addElement( "item 10" )
+						addElement( "item 11" )
+						addElement( "item 12" )
+						addElement( "item 13" )
+						addElement( "item 14" )
+						addElement( "item 15" )
+					}
 					"enabled": false
 					auxiliary() {
 						"JavaCodeGenerator.typeParameters": "String"
+						"JavaCodeGenerator.variableLocal": false
 					}
 				} )
 			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
@@ -62,6 +88,10 @@ new FormModel {
 				add( new FormComponent( "javax.swing.JTree" ) {
 					name: "tree1"
 					"showsRootHandles": true
+					"editable": true
+					auxiliary() {
+						"JavaCodeGenerator.variableLocal": false
+					}
 				} )
 			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
 				"value": "cell 1 1,growx"
@@ -71,6 +101,9 @@ new FormModel {
 				add( new FormComponent( "javax.swing.JTree" ) {
 					name: "tree2"
 					"enabled": false
+					auxiliary() {
+						"JavaCodeGenerator.variableLocal": false
+					}
 				} )
 			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
 				"value": "cell 2 1,growx"
@@ -87,21 +120,101 @@ new FormModel {
 					name: "table1"
 					"model": new com.jformdesigner.model.SwingTableModel( new java.util.Vector {
 						add( new java.util.Vector {
-							add( "Item 1a" )
-							add( "Item 2a" )
+							add( "item 1" )
+							add( "item 1b" )
 							add( "January" )
 							add( "July" )
 							add( 123 )
 							add( null )
 						} )
 						add( new java.util.Vector {
-							add( "Item 1b" )
-							add( "Item 2b" )
+							add( "item 2" )
+							add( "item 2b" )
 							add( "February" )
 							add( "August" )
 							add( 456 )
 							add( true )
 						} )
+						add( new java.util.Vector {
+							add( "item 3" )
+							add( null )
+							add( "March" )
+							add( null )
+							add( null )
+							add( null )
+						} )
+						add( new java.util.Vector {
+							add( "item 4" )
+							add( null )
+							add( "April" )
+							add( null )
+							add( null )
+							add( null )
+						} )
+						add( new java.util.Vector {
+							add( "item 5" )
+							add( null )
+							add( "May" )
+							add( null )
+							add( null )
+							add( null )
+						} )
+						add( new java.util.Vector {
+							add( "item 6" )
+							add( null )
+							add( "June" )
+							add( null )
+							add( null )
+							add( null )
+						} )
+						add( new java.util.Vector {
+							add( "item 7" )
+							add( null )
+							add( "July" )
+							add( null )
+							add( null )
+							add( null )
+						} )
+						add( new java.util.Vector {
+							add( "item 8" )
+							add( null )
+							add( "August" )
+							add( null )
+							add( null )
+							add( null )
+						} )
+						add( new java.util.Vector {
+							add( "item 9" )
+							add( null )
+							add( "September" )
+							add( null )
+							add( null )
+							add( null )
+						} )
+						add( new java.util.Vector {
+							add( "item 10" )
+							add( null )
+							add( "October" )
+							add( null )
+							add( null )
+							add( null )
+						} )
+						add( new java.util.Vector {
+							add( "item 11" )
+							add( null )
+							add( "November" )
+							add( null )
+							add( null )
+							add( null )
+						} )
+						add( new java.util.Vector {
+							add( "item 12" )
+							add( null )
+							add( "December" )
+							add( null )
+							add( null )
+							add( null )
+						} )
 					}, new java.util.Vector {
 						add( "Not editable" )
 						add( "Text" )
@@ -132,10 +245,24 @@ new FormModel {
 						add( null )
 					} )
 					"autoCreateRowSorter": true
+					auxiliary() {
+						"JavaCodeGenerator.variableLocal": false
+					}
 				} )
 			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
 				"value": "cell 1 2 2 1,growx,width 300"
 			} )
+			add( new FormComponent( "javax.swing.JCheckBox" ) {
+				name: "dndCheckBox"
+				"text": "enable drag and drop"
+				"mnemonic": 68
+				auxiliary() {
+					"JavaCodeGenerator.variableLocal": false
+				}
+				addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "dndChanged", false ) )
+			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+				"value": "cell 0 3 3 1"
+			} )
 		}, new FormLayoutConstraints( null ) {
 			"location": new java.awt.Point( 0, 0 )
 			"size": new java.awt.Dimension( 790, 715 )