Theme Editor:

- remember last used preview tab
- sync selected preview tab with all editors

flatlaf-theme-editor/src/main/java/com/formdev/flatlaf/themeeditor/FlatThemePreview.java

@@ -21,6 +21,7 @@ import java.awt.*;
 import java.awt.event.HierarchyEvent;
 import java.util.Map;
 import java.util.WeakHashMap;
+import java.util.prefs.Preferences;
 import javax.swing.*;
 import javax.swing.UIDefaults.ActiveValue;
 import javax.swing.UIDefaults.LazyValue;
@@ -36,20 +37,27 @@ class FlatThemePreview
 	extends JPanel
 	implements DocumentListener
 {
+	private static final String KEY_SELECTED_TAB = "preview.selectedTab";
+
 	private final FlatSyntaxTextArea textArea;
 	private final Timer timer;
+	private final Preferences state;
 
 	private final Map<LazyValue, Object> lazyValueCache = new WeakHashMap<>();
 	private int runWithUIDefaultsGetterLevel;
 
 	FlatThemePreview( FlatSyntaxTextArea textArea ) {
 		this.textArea = textArea;
+		state = Preferences.userRoot().node( FlatThemeFileEditor.PREFS_ROOT_PATH );
 
 		initComponents();
 
+		// add tabs
 		tabbedPane.addTab( "All", createPreviewTab( new FlatThemePreviewAll( this ) ) );
 		tabbedPane.addTab( "Buttons", createPreviewTab( new FlatThemePreviewButtons() ) );
 		tabbedPane.addTab( "Switches", createPreviewTab( new FlatThemePreviewSwitches() ) );
+		selectRecentTab();
+		tabbedPane.addChangeListener( e -> selectedTabChanged() );
 
 		// timer used for delayed preview updates
 		timer = new Timer( 300, e -> update() );
@@ -61,6 +69,7 @@ class FlatThemePreview
 		// update when showing preview (e.g. activating tab)
 		addHierarchyListener( e -> {
 			if( (e.getChangeFlags() & HierarchyEvent.SHOWING_CHANGED) != 0 && isShowing() )
+				selectRecentTab();
 				updateLater();
 		} );
 	}
@@ -74,6 +83,17 @@ class FlatThemePreview
 		return scrollPane;
 	}
 
+	private void selectRecentTab() {
+		int selectedTab = state.getInt( KEY_SELECTED_TAB, -1 );
+		if( selectedTab >= 0 && selectedTab < tabbedPane.getTabCount() )
+			tabbedPane.setSelectedIndex( selectedTab );
+	}
+
+	private void selectedTabChanged() {
+		update();
+		state.putInt( KEY_SELECTED_TAB, tabbedPane.getSelectedIndex() );
+	}
+
 	@Override
 	public void insertUpdate( DocumentEvent e ) {
 		timer.restart();
@@ -169,7 +189,6 @@ class FlatThemePreview
 		{
 			tabbedPane.setLeadingComponent(previewLabel);
 			tabbedPane.setTabAreaAlignment(FlatTabbedPane.TabAreaAlignment.trailing);
-			tabbedPane.addChangeListener(e -> update());
 		}
 		add(tabbedPane, BorderLayout.CENTER);
 

flatlaf-theme-editor/src/main/java/com/formdev/flatlaf/themeeditor/FlatThemePreview.jfd

@@ -9,7 +9,6 @@ new FormModel {
 				name: "tabbedPane"
 				"leadingComponent": new FormReference( "previewLabel" )
 				"tabAreaAlignment": enum com.formdev.flatlaf.extras.components.FlatTabbedPane$TabAreaAlignment trailing
-				addEvent( new FormEvent( "javax.swing.event.ChangeListener", "stateChanged", "update", false ) )
 			}, new FormLayoutConstraints( class java.lang.String ) {
 				"value": "Center"
 			} )