IDEA-183801: force request focus in StructureView by mouse pressed

platform/lang-impl/src/com/intellij/ide/structureView/newStructureView/StructureViewComponent.java

@@ -64,6 +64,7 @@ import javax.swing.tree.TreeSelectionModel;
 import java.awt.*;
 import java.awt.event.KeyAdapter;
 import java.awt.event.KeyEvent;
+import java.awt.event.MouseEvent;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
@@ -71,6 +72,8 @@ import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 
+import static com.intellij.openapi.keymap.impl.IdeMouseEventDispatcher.requestFocusInNonFocusedWindow;
+
 public class StructureViewComponent extends SimpleToolWindowPanel implements TreeActionsOwner, DataProvider, StructureView.Scrollable {
   private static final Logger LOG = Logger.getInstance("#com.intellij.ide.structureView.newStructureView.StructureViewComponent");
 
@@ -852,6 +855,12 @@ public class StructureViewComponent extends SimpleToolWindowPanel implements Tre
     public String getPlace() {
       return ActionPlaces.STRUCTURE_VIEW_TOOLBAR;
     }
+
+    @Override
+    public void processMouseEvent(MouseEvent event) {
+      requestFocusInNonFocusedWindow(event);
+      super.processMouseEvent(event);
+    }
   }
 
   private static class MyPsiTreeChangeListener extends PsiTreeChangeAdapter {

platform/platform-impl/src/com/intellij/openapi/actionSystem/impl/ActionButton.java

@@ -33,6 +33,7 @@ import java.awt.event.*;
 import java.beans.PropertyChangeEvent;
 import java.beans.PropertyChangeListener;
 
+import static com.intellij.openapi.keymap.impl.IdeMouseEventDispatcher.requestFocusInNonFocusedWindow;
 import static java.awt.event.KeyEvent.VK_SPACE;
 
 public class ActionButton extends JComponent implements ActionButtonComponent, AnActionHolder, Accessible {
@@ -360,6 +361,7 @@ public class ActionButton extends JComponent implements ActionButtonComponent, A
   }
 
   protected void processMouseEvent(MouseEvent e) {
+    requestFocusInNonFocusedWindow(e);
     super.processMouseEvent(e);
     if (e.isConsumed()) return;
     boolean skipPress = checkSkipPressForEvent(e);

platform/platform-impl/src/com/intellij/openapi/keymap/impl/IdeMouseEventDispatcher.java

@@ -419,4 +419,35 @@ public final class IdeMouseEventDispatcher {
       blockMode = mode;
     }
   }
+
+  public static void requestFocusInNonFocusedWindow(@NotNull MouseEvent event) {
+    if (event.getID() == MOUSE_PRESSED) {
+      // request focus by mouse pressed before it settles down
+      requestFocusInNonFocusedWindow(event.getComponent());
+    }
+  }
+
+  private static void requestFocusInNonFocusedWindow(@Nullable Component component) {
+    Window window = UIUtil.getWindow(component);
+    if (window != null && !UIUtil.isFocusAncestor(window)) {
+      Component focusable = UIUtil.isFocusable(component) ? component : findDefaultFocusableComponent(component);
+      if (focusable != null) focusable.requestFocus();
+    }
+  }
+
+  @Nullable
+  private static Component findDefaultFocusableComponent(@Nullable Component component) {
+    Container provider = findFocusTraversalPolicyProvider(component);
+    return provider == null ? null : provider.getFocusTraversalPolicy().getDefaultComponent(provider);
+  }
+
+  @Nullable
+  private static Container findFocusTraversalPolicyProvider(@Nullable Component component) {
+    Container container = component == null || component instanceof Container ? (Container)component : component.getParent();
+    while (container != null) {
+      if (container.isFocusCycleRoot() && container.isFocusTraversalPolicyProvider()) return container;
+      container = container.getParent();
+    }
+    return null;
+  }
 }

platform/util/src/com/intellij/util/ui/UIUtil.java

@@ -2556,8 +2556,13 @@ public class UIUtil {
     drawCenteredString(g, rect, str, true, true);
   }
 
-  public static boolean isFocusAncestor(@NotNull final JComponent component) {
-    final Component owner = KeyboardFocusManager.getCurrentKeyboardFocusManager().getFocusOwner();
+  /**
+   * @param component to check whether it has focus within its component hierarchy
+   * @return {@code true} if component or one of its children has focus
+   * @see Component#isFocusOwner()
+   */
+  public static boolean isFocusAncestor(@NotNull Component component) {
+    Component owner = KeyboardFocusManager.getCurrentKeyboardFocusManager().getFocusOwner();
     if (owner == null) return false;
     if (owner == component) return true;
     return SwingUtilities.isDescendingFrom(owner, component);
@@ -2691,7 +2696,7 @@ public class UIUtil {
    * @return {@code true} if component is not {@code null} and can be focused
    * @see Component#isRequestFocusAccepted(boolean, boolean, sun.awt.CausedFocusEvent.Cause)
    */
-  public static boolean isFocusable(JComponent component) {
+  public static boolean isFocusable(@Nullable Component component) {
     return component != null && component.isFocusable() && component.isEnabled() && component.isShowing();
   }