SplitLayoutPanel: Hide Splitters when children are hidden

Fixes issue 7715.

Review-Link: http://gwt-code-reviews.appspot.com/1880804/

Review by: goktug@google.com

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@11453 8db76d5a-ed1c-0410-87a9-c151d255dfc7
diff --git a/user/src/com/google/gwt/user/client/ui/SplitLayoutPanel.java b/user/src/com/google/gwt/user/client/ui/SplitLayoutPanel.java
index 6cb8462..a0acd62 100644
--- a/user/src/com/google/gwt/user/client/ui/SplitLayoutPanel.java
+++ b/user/src/com/google/gwt/user/client/ui/SplitLayoutPanel.java
@@ -141,7 +141,7 @@
           mouseDown = false;
 
           glassElem.removeFromParent();
-          
+
           // Handle double-clicks.
           // Fake them since the double-click event aren't fired.
           if (this.toggleDisplayAllowed) {
@@ -377,6 +377,16 @@
     return false;
   }
 
+  @Override
+  public void setWidgetHidden(Widget widget, boolean hidden) {
+    super.setWidgetHidden(widget, hidden);
+    Splitter splitter = getAssociatedSplitter(widget);
+    if (splitter != null) {
+      // The splitter is null for the center element.
+      super.setWidgetHidden(splitter, hidden);
+    }
+  }
+
   /**
    * Sets the minimum allowable size for the given widget.
    *