 				}
 				
 				// always show menu bar when admin service is present
-				historySlider.alpha = _weaveMenu.alpha = Weave.properties.enableMenuBar.value ? 1.0 : 0.3;
+				if (historySlider)
+					historySlider.alpha = _weaveMenu.alpha = Weave.properties.enableMenuBar.value ? 1.0 : 0.3;
 			}
 			// otherwise there is no menu bar, (which normally includes the oiclogopane, so add one to replace it)
 			else
 			{
-				historySlider.visible = historySlider.includeInLayout = false;
+				if (historySlider)
+					historySlider.visible = historySlider.includeInLayout = false;
 				try
 				{
 		   			if (_weaveMenu && this == _weaveMenu.parent)

			if (!historySlider)
			{
				historySlider = EditorManager.getNewEditor(Weave.history) as UIComponent;
				this.addChildAt(historySlider, this.getChildIndex(visDesktop));
			}
			
			DraggablePanel.adminMode = adminService || getFlashVarEditable();

				
				showHistorySlider = Weave.properties.showSessionHistoryControls.value;
			}
			if (historySlider)
				historySlider.visible = historySlider.includeInLayout = showHistorySlider;
			
			if (Weave.properties.enableWindowMenu.value || adminService)
			{
