IJPL-197361 Multi-selection is not repainted while focus changing

GitOrigin-RevId: 2f2ec413f1e34644a5c43d86b0309d670f2adf1b

platform/platform-api/src/com/intellij/ui/components/WideSelectionListUI.java

@@ -17,6 +17,8 @@ import javax.swing.*;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.basic.BasicListUI;
 import java.awt.*;
+import java.awt.event.FocusEvent;
+import java.awt.event.FocusListener;
 
 import static com.intellij.openapi.util.SystemInfo.isMac;
 import static com.intellij.ui.paint.RectanglePainter.DRAW;
@@ -223,6 +225,32 @@ public final class WideSelectionListUI extends BasicListUI {
     }
   }
 
+  @Override
+  protected FocusListener createFocusListener() {
+    var superFocusListener = super.createFocusListener();
+
+    // Support selected items background while changing focus
+    return new FocusListener() {
+      @Override
+      public void focusGained(FocusEvent e) {
+        if (list.getSelectionMode() == ListSelectionModel.SINGLE_SELECTION) {
+          superFocusListener.focusGained(e);
+        } else {
+          list.repaint();
+        }
+      }
+
+      @Override
+      public void focusLost(FocusEvent e) {
+        if (list.getSelectionMode() == ListSelectionModel.SINGLE_SELECTION) {
+          superFocusListener.focusLost(e);
+        } else {
+          list.repaint();
+        }
+      }
+    };
+  }
+
   /** @noinspection MethodOverridesStaticMethodOfSuperclass, unused */
   public static ComponentUI createUI(JComponent list) {
     return new WideSelectionListUI();

platform/platform-impl/internal/src/com/intellij/internal/ui/sandbox/components/ThreeStateCheckBoxPanel.kt

@@ -10,7 +10,7 @@ import javax.swing.JComponent
 
 internal class ThreeStateCheckBoxPanel : UISandboxPanel {
 
-  override val title: String = "ThreeStateCheckBoxPanel"
+  override val title: String = "ThreeStateCheckBox"
 
   override fun createContent(disposable: Disposable): JComponent {
     return panel {