ComboBox: do not paint arrow button background if it is hidden (issue #915)

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

@@ -585,7 +585,7 @@ public class FlatComboBoxUI
 			FlatUIUtils.paintComponentBackground( g2, 0, 0, width, height, focusWidth, arc );
 
 			// paint arrow button background
-			if( enabled && !isCellRenderer ) {
+			if( enabled && !isCellRenderer && arrowButton.isVisible() ) {
 				Color buttonColor = paintButton
 					? buttonEditableBackground
 					: (buttonFocusedBackground != null || focusedBackground != null) && isPermanentFocusOwner( comboBox )
@@ -612,7 +612,7 @@ public class FlatComboBoxUI
 			}
 
 			// paint vertical line between value and arrow button
-			if( paintButton ) {
+			if( paintButton && arrowButton.isVisible() ) {
 				Color separatorColor = enabled ? buttonSeparatorColor : buttonDisabledSeparatorColor;
 				if( separatorColor != null && buttonSeparatorWidth > 0 ) {
 					g2.setColor( separatorColor );

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

@@ -59,6 +59,11 @@ public class FlatComponentsTest
 		};
 		for( JSlider slider : allSliders )
 			slider.addChangeListener( sliderChanged );
+
+		UIManager.addPropertyChangeListener( e -> {
+			if( "lookAndFeel".equals( e.getPropertyName() ) && hideArrowButtonCheckBox.isSelected() )
+				SwingUtilities.invokeLater( () -> hideArrowButton() );
+		} );
 	}
 
 	private void changeProgress() {
@@ -127,6 +132,18 @@ public class FlatComponentsTest
 		}
 	}
 
+	private void hideArrowButton() {
+		boolean hideArrowButton = hideArrowButtonCheckBox.isSelected();
+
+		for( Component c : getComponents() ) {
+			if( c instanceof JComboBox ) {
+				Component b = ((JComboBox<?>)c).getComponent( 0 );
+				if( b instanceof AbstractButton )
+					b.setVisible( !hideArrowButton );
+			}
+		}
+	}
+
 	private void roundRectChanged() {
 		Boolean roundRect = roundRectCheckBox.isSelected() ? true : null;
 
@@ -380,6 +397,7 @@ public class FlatComponentsTest
 		magentaOutlineRadioButton = new JRadioButton();
 		magentaCyanOutlineRadioButton = new JRadioButton();
 		focusPaintedCheckBox = new JCheckBox();
+		hideArrowButtonCheckBox = new JCheckBox();
 		JLabel scrollBarLabel = new JLabel();
 		JScrollBar scrollBar1 = new JScrollBar();
 		JScrollBar scrollBar4 = new JScrollBar();
@@ -1234,9 +1252,10 @@ public class FlatComponentsTest
 				"[]" +
 				"[]",
 				// rows
-				"[]" +
-				"[]" +
-				"[]" +
+				"[]0" +
+				"[]0" +
+				"[]0" +
+				"[]0" +
 				"[]"));
 
 			//---- buttonTypeComboBox ----
@@ -1290,13 +1309,18 @@ public class FlatComponentsTest
 				magentaCyanOutlineRadioButton.addActionListener(e -> outlineChanged());
 				panel4.add(magentaCyanOutlineRadioButton);
 			}
-			panel5.add(panel4, "cell 0 2 1 2");
+			panel5.add(panel4, "cell 0 2 1 3");
 
 			//---- focusPaintedCheckBox ----
 			focusPaintedCheckBox.setText("focusPainted");
 			focusPaintedCheckBox.setSelected(true);
 			focusPaintedCheckBox.addActionListener(e -> focusPaintedChanged());
 			panel5.add(focusPaintedCheckBox, "cell 1 2");
+
+			//---- hideArrowButtonCheckBox ----
+			hideArrowButtonCheckBox.setText("hide arrow button");
+			hideArrowButtonCheckBox.addActionListener(e -> hideArrowButton());
+			panel5.add(hideArrowButtonCheckBox, "cell 1 3");
 		}
 		add(panel5, "cell 5 13 2 10,grow");
 
@@ -1703,6 +1727,7 @@ public class FlatComponentsTest
 	private JRadioButton magentaOutlineRadioButton;
 	private JRadioButton magentaCyanOutlineRadioButton;
 	private JCheckBox focusPaintedCheckBox;
+	private JCheckBox hideArrowButtonCheckBox;
 	private JSlider slider1;
 	private JSlider slider6;
 	private JCheckBox sliderPaintTrackCheckBox;

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

@@ -1,4 +1,4 @@
-JFDML JFormDesigner: "7.0.5.0.404" Java: "17.0.2" encoding: "UTF-8"
+JFDML JFormDesigner: "8.3" encoding: "UTF-8"
 
 new FormModel {
 	contentType: "form/swing"
@@ -993,7 +993,7 @@ new FormModel {
 			} )
 			add( new FormContainer( "javax.swing.JPanel", new FormLayoutManager( class net.miginfocom.swing.MigLayout ) {
 				"$columnConstraints": "[][]"
-				"$rowConstraints": "[][][][]"
+				"$rowConstraints": "[]0[]0[]0[]0[]"
 				"$layoutConstraints": "ltr,insets dialog,hidemode 3"
 			} ) {
 				name: "panel5"
@@ -1092,7 +1092,7 @@ new FormModel {
 						addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "outlineChanged", false ) )
 					} )
 				}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
-					"value": "cell 0 2 1 2"
+					"value": "cell 0 2 1 3"
 				} )
 				add( new FormComponent( "javax.swing.JCheckBox" ) {
 					name: "focusPaintedCheckBox"
@@ -1105,6 +1105,16 @@ new FormModel {
 				}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
 					"value": "cell 1 2"
 				} )
+				add( new FormComponent( "javax.swing.JCheckBox" ) {
+					name: "hideArrowButtonCheckBox"
+					"text": "hide arrow button"
+					auxiliary() {
+						"JavaCodeGenerator.variableLocal": false
+					}
+					addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "hideArrowButton", false ) )
+				}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+					"value": "cell 1 3"
+				} )
 			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
 				"value": "cell 5 13 2 10,grow"
 			} )