IDEA-142715 It's impossible to move multiple files by mouse between changelists or even select several files via Ctrl/Cmd+Click

MouseEvent conversion loses the META_MASK modifier, so we should use getModifiers()|getModifiersEx() to copy all masks.

platform/platform-api/src/com/intellij/openapi/actionSystem/ex/ComboBoxAction.java

@@ -198,7 +198,7 @@ public abstract class ComboBoxAction extends AnAction implements CustomComponent
           mouseMoved(MouseEventAdapter.convert(e, e.getComponent(),
                                                MouseEvent.MOUSE_MOVED,
                                                e.getWhen(),
-                                               e.getModifiers(),
+                                               e.getModifiers() | e.getModifiersEx(),
                                                e.getX(),
                                                e.getY()));
         }

platform/platform-impl/src/com/intellij/ide/IdeEventQueue.java

@@ -352,7 +352,7 @@ public class IdeEventQueue extends EventQueue {
         lastMouseWheel = System.currentTimeMillis();
 
         MouseWheelEvent newMouseWheelEvent = MouseEventAdapter.convert(mwe,
-          wheelDestinationComponent, mwe.getID(), lastMouseWheel, mwe.getModifiers(), mwe.getX(), mwe.getY()
+          wheelDestinationComponent, mwe.getID(), lastMouseWheel, mwe.getModifiers() | mwe.getModifiersEx(), mwe.getX(), mwe.getY()
         );
         return newMouseWheelEvent;
       }

platform/platform-impl/src/com/intellij/openapi/wm/impl/IdeGlassPaneImpl.java

@@ -406,7 +406,7 @@ public class IdeGlassPaneImpl extends JPanel implements IdeGlassPaneEx, IdeEvent
 
   private static MouseEvent convertEvent(final MouseEvent e, final Component target) {
     final Point point = SwingUtilities.convertPoint(e.getComponent(), e.getPoint(), target);
-    return MouseEventAdapter.convert(e, target, e.getID(), e.getWhen(), e.getModifiersEx(), point.x, point.y);
+    return MouseEventAdapter.convert(e, target, point.x, point.y);
   }
 
   private static void fireMouseEvent(final MouseListener listener, final MouseEvent event) {

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

@@ -98,7 +98,7 @@ public class MouseEventAdapter<T> implements MouseListener, MouseMotionListener,
   }
 
   public static MouseEvent convert(MouseEvent event, Component source, int x, int y) {
-    return convert(event, source, event.getID(), event.getWhen(), event.getModifiers(), x, y);
+    return convert(event, source, event.getID(), event.getWhen(), event.getModifiers() | event.getModifiersEx(), x, y);
   }
 
   public static MouseEvent convert(MouseEvent event, Component source, int id, long when, int modifiers, int x, int y) {