diff --git a/editor/libeditor/base/nsEditor.cpp b/editor/libeditor/base/nsEditor.cpp
index b437e1e2991..4bf8530a682 100644
--- a/editor/libeditor/base/nsEditor.cpp
+++ b/editor/libeditor/base/nsEditor.cpp
@@ -1982,8 +1982,15 @@ nsEditor::QueryComposition(nsTextEventReply* aReply)
 
       // XXX_kin: END HACK! HACK! HACK!
 
-      result = caretP->GetCaretCoordinates(nsCaret::eIMECoordinates, selection,
-		                      &(aReply->mCursorPosition), &(aReply->mCursorIsCollapsed), nsnull);
+      nsIView *view = nsnull;
+      result =
+        caretP->GetCaretCoordinates(nsCaret::eIMECoordinates,
+                                    selection,
+                                    &(aReply->mCursorPosition),
+                                    &(aReply->mCursorIsCollapsed),
+                                    &view);
+      if (NS_SUCCEEDED(result) && view)
+        aReply->mReferenceWidget = view->GetWidget();
     }
   }
   return result;
diff --git a/editor/libeditor/text/nsPlaintextEditor.cpp b/editor/libeditor/text/nsPlaintextEditor.cpp
index 62ca609a736..758cfdc20e5 100644
--- a/editor/libeditor/text/nsPlaintextEditor.cpp
+++ b/editor/libeditor/text/nsPlaintextEditor.cpp
@@ -1736,12 +1736,15 @@ nsPlaintextEditor::SetCompositionString(const nsAString& aCompositionString, nsI
 
   if (caretP)
   {
+    nsIView *view = nsnull;
     result = caretP->GetCaretCoordinates(nsCaret::eIMECoordinates,
                                          selection,
                                          &(aReply->mCursorPosition),
                                          &(aReply->mCursorIsCollapsed),
-                                         nsnull);
+                                         &view);
     NS_ASSERTION(NS_SUCCEEDED(result), "cannot get caret position");
+    if (NS_SUCCEEDED(result) && view)
+      aReply->mReferenceWidget = view->GetWidget();
   }
 
   return result;
diff --git a/widget/public/nsGUIEvent.h b/widget/public/nsGUIEvent.h
index 4373a378c34..52b38e03aa6 100644
--- a/widget/public/nsGUIEvent.h
+++ b/widget/public/nsGUIEvent.h
@@ -790,12 +790,13 @@ typedef nsTextRange* nsTextRangeArray;
 struct nsTextEventReply
 {
   nsTextEventReply()
-    : mCursorIsCollapsed(PR_FALSE)
+    : mCursorIsCollapsed(PR_FALSE), mReferenceWidget(nsnull)
   {
   }
 
   nsRect mCursorPosition;
   PRBool mCursorIsCollapsed;
+  nsIWidget* mReferenceWidget;
 };
 
 typedef struct nsTextEventReply nsTextEventReply;
diff --git a/widget/src/gtk2/nsWindow.cpp b/widget/src/gtk2/nsWindow.cpp
index 4a24cbf0d12..bc40ee00590 100644
--- a/widget/src/gtk2/nsWindow.cpp
+++ b/widget/src/gtk2/nsWindow.cpp
@@ -5574,20 +5574,7 @@ nsWindow::IMEComposeStart(void)
     if (NS_UNLIKELY(mIsDestroyed))
         return;
 
-    gint x1, y1, x2, y2;
-    GtkWidget *widget =
-        get_gtk_widget_for_gdk_window(this->mDrawingarea->inner_window);
-
-    gdk_window_get_origin(widget->window, &x1, &y1);
-    gdk_window_get_origin(this->mDrawingarea->inner_window, &x2, &y2);
-
-    GdkRectangle area;
-    area.x = compEvent.theReply.mCursorPosition.x + (x2 - x1);
-    area.y = compEvent.theReply.mCursorPosition.y + (y2 - y1);
-    area.width  = 0;
-    area.height = compEvent.theReply.mCursorPosition.height;
-
-    gtk_im_context_set_cursor_location(IMEGetContext(), &area);
+    IMESetCursorPosition(compEvent.theReply);
 }
 
 void
@@ -5633,20 +5620,7 @@ nsWindow::IMEComposeText(const PRUnichar *aText,
     if (NS_UNLIKELY(mIsDestroyed))
         return;
 
-    gint x1, y1, x2, y2;
-    GtkWidget *widget =
-        get_gtk_widget_for_gdk_window(this->mDrawingarea->inner_window);
-
-    gdk_window_get_origin(widget->window, &x1, &y1);
-    gdk_window_get_origin(this->mDrawingarea->inner_window, &x2, &y2);
-
-    GdkRectangle area;
-    area.x = textEvent.theReply.mCursorPosition.x + (x2 - x1);
-    area.y = textEvent.theReply.mCursorPosition.y + (y2 - y1);
-    area.width  = 0;
-    area.height = textEvent.theReply.mCursorPosition.height;
-
-    gtk_im_context_set_cursor_location(IMEGetContext(), &area);
+    IMESetCursorPosition(textEvent.theReply);
 }
 
 void
@@ -5781,6 +5755,42 @@ nsWindow::IMEFilterEvent(GdkEventKey *aEvent)
     return retval;
 }
 
+void
+nsWindow::IMESetCursorPosition(const nsTextEventReply& aReply)
+{
+    nsIWidget *refWidget = aReply.mReferenceWidget;
+    if (!refWidget) {
+        NS_WARNING("mReferenceWidget is null");
+        refWidget = this;
+    }
+    nsWindow* refWindow = static_cast<nsWindow*>(refWidget);
+
+    nsWindow* ownerWindow = IM_get_owning_window(mDrawingarea);
+    if (!ownerWindow) {
+        NS_ERROR("there is no owner");
+        return;
+    }
+
+    // Get the position of the refWindow in screen.
+    gint refX, refY;
+    gdk_window_get_origin(refWindow->mDrawingarea->inner_window,
+                          &refX, &refY);
+
+    // Get the position of IM context owner window in screen.
+    gint ownerX, ownerY;
+    gdk_window_get_origin(ownerWindow->mDrawingarea->inner_window,
+                          &ownerX, &ownerY);
+
+    // Compute the caret position in the IM owner window.
+    GdkRectangle area;
+    area.x = aReply.mCursorPosition.x + refX - ownerX;
+    area.y = aReply.mCursorPosition.y + refY - ownerY;
+    area.width  = 0;
+    area.height = aReply.mCursorPosition.height;
+
+    gtk_im_context_set_cursor_location(IMEGetContext(), &area);
+}
+
 NS_IMETHODIMP
 nsWindow::ResetInputState()
 {
diff --git a/widget/src/gtk2/nsWindow.h b/widget/src/gtk2/nsWindow.h
index 660379af822..6db1d63ea7e 100644
--- a/widget/src/gtk2/nsWindow.h
+++ b/widget/src/gtk2/nsWindow.h
@@ -294,6 +294,7 @@ public:
     nsWindow*          IMEComposingWindow(void);
     void               IMECreateContext  (void);
     PRBool             IMEFilterEvent    (GdkEventKey *aEvent);
+    void               IMESetCursorPosition(const nsTextEventReply& aReply);
 
     /*
      *  |mIMEData| has all IME data for the window and its children widgets.