diff --git a/widget/src/gtk/nsWidget.cpp b/widget/src/gtk/nsWidget.cpp
index 174fcfdf6aaf..3d3c641efb20 100644
--- a/widget/src/gtk/nsWidget.cpp
+++ b/widget/src/gtk/nsWidget.cpp
@@ -224,6 +224,7 @@ nsWidget::nsWidget()
   mPreferredWidth  = 0;
   mPreferredHeight = 0;
   mShown = PR_FALSE;
+  mInternalShown = PR_FALSE;
   mBounds.x = 0;
   mBounds.y = 0;
   mBounds.width = 0;
@@ -438,20 +439,52 @@ NS_IMETHODIMP nsWidget::Show(PRBool bState)
   if (!mWidget)
     return NS_OK; // Will be null durring printing
 
-  if (bState) {
-    gtk_widget_show(mWidget);
-    gtk_widget_show(mMozBox);
-  }
-  else {
-    gtk_widget_hide(mMozBox);
-    gtk_widget_hide(mWidget);
-  }
-
   mShown = bState;
 
+  ResetInternalVisibility();
+
   return NS_OK;
 }
 
+void nsWidget::ResetInternalVisibility()
+{
+  PRBool show = mShown;
+  if (show) {
+    if (mParent != nsnull) {
+      nsRect parentBounds;
+      mParent->GetClientBounds(parentBounds);
+      parentBounds.x = parentBounds.y = 0;
+      nsRect myBounds;
+      GetBounds(myBounds);
+      if (!myBounds.Intersects(parentBounds)) {
+        show = PR_FALSE;
+      }
+    }
+  }
+
+  if (show == mInternalShown) {
+    return;
+  }
+
+  SetInternalVisibility(show);
+}
+
+void nsWidget::SetInternalVisibility(PRBool aVisible)
+{
+  mInternalShown = aVisible;
+
+  if (aVisible) {
+    if (mWidget)
+      gtk_widget_show(mWidget);
+    if (mMozBox)
+      gtk_widget_show(mMozBox);
+  } else {
+    if (mWidget)
+      gtk_widget_hide(mWidget);
+    if (mMozBox)
+      gtk_widget_hide(mMozBox);
+  }
+}
 
 NS_IMETHODIMP nsWidget::CaptureRollupEvents(nsIRollupListener * aListener, PRBool aDoCapture, PRBool aConsumeRollupEvent)
 {
@@ -548,12 +581,13 @@ NS_IMETHODIMP nsWidget::Move(PRInt32 aX, PRInt32 aY)
   mBounds.x = aX;
   mBounds.y = aY;
 
-
   if (mMozBox) 
   {
     gtk_mozbox_set_position(GTK_MOZBOX(mMozBox), aX, aY);
   }
 
+  ResetInternalVisibility();
+
   return NS_OK;
 }
 
@@ -571,6 +605,17 @@ NS_IMETHODIMP nsWidget::Resize(PRInt32 aWidth, PRInt32 aHeight, PRBool aRepaint)
   if (mWidget)
     gtk_widget_set_usize(mWidget, aWidth, aHeight);
 
+  ResetInternalVisibility();
+  PRUint32 childCount, index;
+  if (NS_SUCCEEDED(mChildren->Count(&childCount))) {
+    for (index = 0; index < childCount; index++) {
+      nsCOMPtr<nsIWidget> childWidget;
+      if (NS_SUCCEEDED(mChildren->QueryElementAt(index, NS_GET_IID(nsIWidget), (void**)getter_AddRefs(childWidget)))) {
+        NS_STATIC_CAST(nsWidget*, NS_STATIC_CAST(nsIWidget*, childWidget.get()))->ResetInternalVisibility();
+      }
+    }
+  }
+
   return NS_OK;
 }
 
@@ -615,6 +660,8 @@ PRBool nsWidget::OnResize(nsRect &aRect)
   mBounds.width = aRect.width;
   mBounds.height = aRect.height;
 
+  ResetInternalVisibility();
+
   NS_ADDREF_THIS();
   PRBool result = OnResize(&event);
   NS_RELEASE_THIS();
@@ -636,6 +683,8 @@ PRBool nsWidget::OnMove(PRInt32 aX, PRInt32 aY)
     mBounds.x = aX;
     mBounds.y = aY;
 
+    ResetInternalVisibility();
+
     nsGUIEvent event;
     InitEvent(event, NS_MOVE);
     event.point.x = aX;
diff --git a/widget/src/gtk/nsWidget.h b/widget/src/gtk/nsWidget.h
index 0726091f6c3c..3eec27fd1942 100644
--- a/widget/src/gtk/nsWidget.h
+++ b/widget/src/gtk/nsWidget.h
@@ -308,7 +308,18 @@ protected:
 public:
   virtual void IMECommitEvent(GdkEventKey *aEvent);
 
+  // This MUST be called after you change the widget bounds
+  // or after the parent's size changes
+  // or when you show the widget
+  // We will decide whether to really show the widget or not
+  // We will hide the widget if it doesn't overlap the parent bounds
+  // This reduces problems with 16-bit coordinates wrapping.
+  virtual void ResetInternalVisibility();
+
 protected:
+  // override this method to do whatever you have to do to make this widget
+  // visible or invisibile --- i.e., the real work of Show()
+  virtual void SetInternalVisibility(PRBool aVisible);
 
   //////////////////////////////////////////////////////////////////
   //
@@ -376,10 +387,10 @@ protected:
   // Invalidate)
   nsCOMPtr<nsIRegion> mUpdateArea;
 
-  PRBool mShown;
-
   PRUint32 mPreferredWidth, mPreferredHeight;
-  PRBool       mListenForResizes;
+  PRPackedBool mListenForResizes;
+  PRPackedBool mShown;
+  PRPackedBool mInternalShown;
 
   // this is the rollup listener variables
   static nsCOMPtr<nsIRollupListener> gRollupListener;
diff --git a/widget/src/gtk/nsWindow.cpp b/widget/src/gtk/nsWindow.cpp
index 8ef6d3123e63..24982bc923aa 100644
--- a/widget/src/gtk/nsWindow.cpp
+++ b/widget/src/gtk/nsWindow.cpp
@@ -2297,7 +2297,9 @@ NS_IMETHODIMP nsWindow::Scroll(PRInt32 aDx, PRInt32 aDy, nsRect *aClipRect)
         child->GetBounds(bounds);
         bounds.x += aDx;
         bounds.y += aDy;
-        NS_STATIC_CAST(nsBaseWidget*, (nsIWidget*)child)->SetBounds(bounds);
+        nsWidget* childWidget = NS_STATIC_CAST(nsWidget*, NS_STATIC_CAST(nsIWidget*, child.get()));
+        childWidget->SetBounds(bounds);
+        childWidget->ResetInternalVisibility();
       }
 
       if (NS_FAILED(children->Next()))
@@ -2561,13 +2563,33 @@ NS_IMETHODIMP nsWindow::Show(PRBool bState)
 
   mShown = bState;
 
+  // show
+  ResetInternalVisibility();
 
+  return NS_OK;
+}
+
+void nsWindow::ResetInternalVisibility()
+{
+  if (mShell)
+  { // top level, always set the visibility regardless of parent geometry
+    SetInternalVisibility(mShown);
+  }
+  else
+  {
+    nsWidget::ResetInternalVisibility();
+  }
+}
+
+void nsWindow::SetInternalVisibility(PRBool aVisible)
+{
   // don't show if we are too small
   if (mIsTooSmall)
-    return NS_OK;
+    return;
 
-  // show
-  if (bState)
+  mInternalShown = aVisible;
+
+  if (aVisible)
   {
     // show mSuperWin
     gdk_window_show(mSuperWin->bin_window);
@@ -2601,8 +2623,6 @@ NS_IMETHODIMP nsWindow::Show(PRBool bState)
     } 
 
   }
-
-  return NS_OK;
 }
 
 //-------------------------------------------------------------------------
@@ -2688,6 +2708,8 @@ NS_IMETHODIMP nsWindow::Move(PRInt32 aX, PRInt32 aY)
   mBounds.x = aX;
   mBounds.y = aY;
 
+  ResetInternalVisibility();
+
   if (mIsToplevel && mShell)
   {
 #ifdef DEBUG
@@ -2736,6 +2758,17 @@ NS_IMETHODIMP nsWindow::Resize(PRInt32 aWidth, PRInt32 aHeight, PRBool aRepaint)
   mBounds.width  = aWidth;
   mBounds.height = aHeight;
 
+  ResetInternalVisibility();
+  PRUint32 childCount, index;
+  if (NS_SUCCEEDED(mChildren->Count(&childCount))) {
+    for (index = 0; index < childCount; index++) {
+      nsCOMPtr<nsIWidget> childWidget;
+      if (NS_SUCCEEDED(mChildren->QueryElementAt(index, NS_GET_IID(nsIWidget), (void**)getter_AddRefs(childWidget)))) {
+        NS_STATIC_CAST(nsWidget*, NS_STATIC_CAST(nsIWidget*, childWidget.get()))->ResetInternalVisibility();
+      }
+    }
+  }
+
   // code to keep the window from showing before it has been moved or resized
 
   // if we are resized to 1x1 or less, we will hide the window.  Show(TRUE) will be ignored until a
@@ -2773,6 +2806,7 @@ NS_IMETHODIMP nsWindow::Resize(PRInt32 aWidth, PRInt32 aHeight, PRBool aRepaint)
       gdk_window_hide(mSuperWin->bin_window);
       gdk_window_hide(mSuperWin->shell_window);
     }
+    mInternalShown = PR_FALSE;
   }
   else
   {
@@ -2823,8 +2857,9 @@ NS_IMETHODIMP nsWindow::Resize(PRInt32 aWidth, PRInt32 aHeight, PRBool aRepaint)
     //g_print("not sending resize event\n");
   }
 
-  if (nNeedToShow)
+  if (nNeedToShow) {
     Show(PR_TRUE);
+  }
 
   if (aRepaint)
     Invalidate(PR_FALSE);
diff --git a/widget/src/gtk/nsWindow.h b/widget/src/gtk/nsWindow.h
index 4907025b2838..4d0b22cae110 100644
--- a/widget/src/gtk/nsWindow.h
+++ b/widget/src/gtk/nsWindow.h
@@ -198,6 +198,8 @@ public:
   static void ClearIconEntry(PLDHashTable* aTable, PLDHashEntryHdr* aHdr);
 
 protected:
+  virtual void ResetInternalVisibility();
+  virtual void SetInternalVisibility(PRBool aVisible);
 
   virtual void OnRealize(GtkWidget *aWidget);