Demo: ExtrasPanel:

- animate "rainbow" icon only if extras tab is visible
- recreated added components in JFormDesigner

flatlaf-demo/src/main/java/com/formdev/flatlaf/demo/extras/ExtrasPanel.java

@@ -22,6 +22,7 @@ import com.formdev.flatlaf.extras.FlatSVGIcon.ColorFilter;
 import com.formdev.flatlaf.extras.components.FlatTriStateCheckBox;
 import net.miginfocom.swing.*;
 import java.awt.*;
+import java.awt.event.HierarchyEvent;
 
 /**
  * @author Karl Tauber
@@ -29,7 +30,8 @@ import java.awt.*;
 public class ExtrasPanel
 	extends JPanel
 {
-	public int counter = 0;
+	private Timer rainbowIconTimer;
+	private int rainbowCounter = 0;
 
 	public ExtrasPanel() {
 		initComponents();
@@ -54,6 +56,34 @@ public class ExtrasPanel
 		addSVGIcon( "errorDialog.svg" );
 		addSVGIcon( "informationDialog.svg" );
 		addSVGIcon( "warningDialog.svg" );
+
+		initRainbowIcon();
+	}
+
+	private void initRainbowIcon() {
+		FlatSVGIcon icon = new FlatSVGIcon( "com/formdev/flatlaf/demo/extras/svg/informationDialog.svg" );
+		icon.setColorFilter( new ColorFilter( color -> {
+			rainbowCounter += 1;
+			rainbowCounter %= 255;
+			return Color.getHSBColor( rainbowCounter / 255f, 1, 1 );
+		} ) );
+		rainbowIcon.setIcon( icon );
+
+		rainbowIconTimer = new Timer( 30, e -> {
+			rainbowIcon.repaint();
+		} );
+
+		// start rainbow timer only if panel is shown ("Extras" tab is active)
+		addHierarchyListener( e -> {
+			if( e.getID() == HierarchyEvent.HIERARCHY_CHANGED &&
+				(e.getChangeFlags() & HierarchyEvent.SHOWING_CHANGED) != 0 )
+			{
+				if( isShowing() )
+					rainbowIconTimer.start();
+				else
+					rainbowIconTimer.stop();
+			}
+		} );
 	}
 
 	private void addSVGIcon( String name ) {
@@ -64,6 +94,16 @@ public class ExtrasPanel
 		triStateLabel1.setText( triStateCheckBox1.getState().toString() );
 	}
 
+	private void brighterChanged() {
+		FlatSVGIcon.ColorFilter.getInstance().setMapper( brighterToggleButton.isSelected()
+			? color -> color.brighter().brighter()
+			: null );
+
+		// repaint whole application window because global color filter also affects
+		// icons in menubar, toolbar, etc.
+		SwingUtilities.windowForComponent( this ).repaint();
+	}
+
 	private void initComponents() {
 		// JFormDesigner - Component initialization - DO NOT MODIFY  //GEN-BEGIN:initComponents
 		label4 = new JLabel();
@@ -76,9 +116,9 @@ public class ExtrasPanel
 		separator1 = new JSeparator();
 		label5 = new JLabel();
 		label6 = new JLabel();
-		label7 = new JLabel();
 		rainbowIcon = new JLabel();
-		toggleButton1 = new JToggleButton();
+		label7 = new JLabel();
+		brighterToggleButton = new JToggleButton();
 
 		//======== this ========
 		setLayout(new MigLayout(
@@ -94,6 +134,7 @@ public class ExtrasPanel
 			"[]" +
 			"[]" +
 			"[]" +
+			"[]" +
 			"[]"));
 
 		//---- label4 ----
@@ -132,55 +173,28 @@ public class ExtrasPanel
 		//---- label3 ----
 		label3.setText("The icons may change colors when switching to another theme.");
 		add(label3, "cell 1 3 2 1");
-
+		add(separator1, "cell 1 4 2 1,growx");
-		add(separator1, "cell 1 4, grow");
 
 		//---- label5 ----
 		label5.setText("Color filters can be also applied to icons. Globally or for each instance.");
-		add(label5, "cell 1 5");
+		add(label5, "cell 1 5 2 1");
 
 		//---- label6 ----
-		label6.setText( "Rainbow color filter" );
+		label6.setText("Rainbow color filter");
-		add(label6, "cell 1 6");
+		add(label6, "cell 1 6 2 1");
-
+		add(rainbowIcon, "cell 1 6 2 1");
-		//---- rainbowIcon ----
-		rainbowIcon = createRainbowIcon("informationDialog.svg");
-		add(rainbowIcon, "cell 1 6");
 
 		//---- label7 ----
-		label7.setText( "Global icon color filter" );
+		label7.setText("Global icon color filter");
-		add(label7, "cell 1 7");
+		add(label7, "cell 1 7 2 1");
-
-		// ---- button1 ----
-		toggleButton1.setText( "Toggle brighter" );
-		add(toggleButton1, "cell 1 7");
-
-		// ---- toggleButton1 ----
-		toggleButton1.addActionListener( (e) -> {
-			if (toggleButton1.isSelected())
-				FlatSVGIcon.ColorFilter.getInstance().setMapper( color -> color.brighter() );
-			else
-				FlatSVGIcon.ColorFilter.getInstance().setMapper( null );
-			SwingUtilities.getRootPane( toggleButton1 ).repaint();
-		} );
 
+		//---- brighterToggleButton ----
+		brighterToggleButton.setText("Toggle brighter");
+		brighterToggleButton.addActionListener(e -> brighterChanged());
+		add(brighterToggleButton, "cell 1 7 2 1");
 		// JFormDesigner - End of component initialization  //GEN-END:initComponents
 	}
 
-	private JLabel createRainbowIcon(String name) {
-		FlatSVGIcon rainbowIcon = new FlatSVGIcon( "com/formdev/flatlaf/demo/extras/svg/" + name);
-		rainbowIcon.setColorFilter( new ColorFilter( (color) -> {
-			counter+=1;
-			counter%=255;
-			return Color.getHSBColor(counter/255f, 1, 1);
-		}) );
-		JLabel label = new JLabel(rainbowIcon);
-		new Timer(30, (e) -> {
-			label.repaint();
-		}).start();
-		return label;
-	}
-
 	// JFormDesigner - Variables declaration - DO NOT MODIFY  //GEN-BEGIN:variables
 	private JLabel label4;
 	private JLabel label1;
@@ -189,11 +203,11 @@ public class ExtrasPanel
 	private JLabel label2;
 	private JPanel svgIconsPanel;
 	private JLabel label3;
+	private JSeparator separator1;
 	private JLabel label5;
 	private JLabel label6;
-	private JLabel label7;
-	private JSeparator separator1;
 	private JLabel rainbowIcon;
-	private JToggleButton toggleButton1;
+	private JLabel label7;
+	private JToggleButton brighterToggleButton;
 	// JFormDesigner - End of variables declaration  //GEN-END:variables
 }

flatlaf-demo/src/main/java/com/formdev/flatlaf/demo/extras/ExtrasPanel.jfd

@@ -1,4 +1,4 @@
-JFDML JFormDesigner: "7.0.2.0.298" Java: "14" encoding: "UTF-8"
+JFDML JFormDesigner: "7.0.3.1.342" Java: "16" encoding: "UTF-8"
 
 new FormModel {
 	contentType: "form/swing"
@@ -6,7 +6,7 @@ new FormModel {
 		add( new FormContainer( "javax.swing.JPanel", new FormLayoutManager( class net.miginfocom.swing.MigLayout ) {
 			"$layoutConstraints": "insets dialog,hidemode 3"
 			"$columnConstraints": "[][][left]"
-			"$rowConstraints": "[]para[][][]"
+			"$rowConstraints": "[]para[][][][][][][]"
 		} ) {
 			name: "this"
 			add( new FormComponent( "javax.swing.JLabel" ) {
@@ -56,6 +56,41 @@ new FormModel {
 			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
 				"value": "cell 1 3 2 1"
 			} )
+			add( new FormComponent( "javax.swing.JSeparator" ) {
+				name: "separator1"
+			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+				"value": "cell 1 4 2 1,growx"
+			} )
+			add( new FormComponent( "javax.swing.JLabel" ) {
+				name: "label5"
+				"text": "Color filters can be also applied to icons. Globally or for each instance."
+			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+				"value": "cell 1 5 2 1"
+			} )
+			add( new FormComponent( "javax.swing.JLabel" ) {
+				name: "label6"
+				"text": "Rainbow color filter"
+			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+				"value": "cell 1 6 2 1"
+			} )
+			add( new FormComponent( "javax.swing.JLabel" ) {
+				name: "rainbowIcon"
+			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+				"value": "cell 1 6 2 1"
+			} )
+			add( new FormComponent( "javax.swing.JLabel" ) {
+				name: "label7"
+				"text": "Global icon color filter"
+			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+				"value": "cell 1 7 2 1"
+			} )
+			add( new FormComponent( "javax.swing.JToggleButton" ) {
+				name: "brighterToggleButton"
+				"text": "Toggle brighter"
+				addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "brighterChanged", false ) )
+			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+				"value": "cell 1 7 2 1"
+			} )
 		}, new FormLayoutConstraints( null ) {
 			"location": new java.awt.Point( 0, 0 )
 			"size": new java.awt.Dimension( 500, 300 )