ComboBox (not editable): fixed background painted outside of border if round edges are enabled (similar to issue #382; regression since fixing #330 in FlatLaf 1.4)

CHANGELOG.md

@@ -13,6 +13,9 @@ FlatLaf Change Log
 
 #### Fixed bugs
 
+- ComboBox (not editable): Fixed background painted outside of border if round
+  edges are enabled (client property `JComponent.roundRect` is `true`). (similar
+  to issue #382; regression since fixing #330 in FlatLaf 1.4)
 - Tree: Fixed editing cell issue with custom cell renderer and cell editor that
   use same component for rendering and editing. (issue #385)
 
@@ -41,7 +44,7 @@ FlatLaf Change Log
 - ComboBox (editable): Fixed wrong border of internal text field under special
   circumstances.
 - Spinner: Fixed painting of border corners on left side. (issue #382;
-  regression since FlatLaf 1.4)
+  regression since fixing #330 in FlatLaf 1.4)
 - TableHeader: Do not show resize cursor for last column if resizing last column
   is not possible because auto resize mode of table is not off. (issue #332)
 - TableHeader: Fixed missing trailing vertical separator line if used in upper

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

@@ -555,6 +555,22 @@ public class FlatComboBoxUI
 	@Override
 	@SuppressWarnings( "unchecked" )
 	public void paintCurrentValue( Graphics g, Rectangle bounds, boolean hasFocus ) {
+		// apply clipping using rounded rectangle to avoid that renderer paints
+		// outside of border if combobox uses larger arc for edges
+		// (e.g. FlatClientProperties.COMPONENT_ROUND_RECT is true)
+		FlatBorder border = FlatUIUtils.getOutsideFlatBorder( comboBox );
+		if( border != null ) {
+			int clipArc = border.getArc( comboBox ) - (border.getLineWidth( comboBox ) * 2);
+			if( clipArc > 0 ) {
+				int x = bounds.x;
+				int width = bounds.width + bounds.height;
+				if( !comboBox.getComponentOrientation().isLeftToRight() )
+					x -= bounds.height;
+				((Graphics2D)g).clip( FlatUIUtils.createComponentRectangle(
+					x, bounds.y, width, bounds.height, scale( (float) clipArc ) ) );
+			}
+		}
+
 		paddingBorder.uninstall();
 
 		ListCellRenderer<Object> renderer = comboBox.getRenderer();