diff --git a/platform/platform-api/src/com/intellij/ui/tabs/impl/DragHelper.java b/platform/platform-api/src/com/intellij/ui/tabs/impl/DragHelper.java
index 523683496154..7bc367c7e958 100644
--- a/platform/platform-api/src/com/intellij/ui/tabs/impl/DragHelper.java
+++ b/platform/platform-api/src/com/intellij/ui/tabs/impl/DragHelper.java
@@ -93,7 +93,7 @@ class DragHelper extends MouseDragHelper {
   }
 
   protected void processDrag(MouseEvent event, Point targetScreenPoint, Point startPointScreen) {
-    if (!myTabs.isTabDraggingEnabled()) return;
+    if (!myTabs.isTabDraggingEnabled() || !isDragSource(event)) return;
 
     SwingUtilities.convertPointFromScreen(startPointScreen, myTabs);
 
@@ -165,6 +165,14 @@ class DragHelper extends MouseDragHelper {
     }
   }
 
+  private boolean isDragSource(MouseEvent event) {
+    final Object source = event.getSource();
+    if (source instanceof Component) {
+      return SwingUtilities.windowForComponent(myTabs) == SwingUtilities.windowForComponent((Component)source);
+    }
+    return false;
+  }
+
   private TabLabel findMostOverlapping(Axis measurer, TabLabel... labels) {
     double freeSpace;