Problem Description:

A Javascript error thrown when right clicking spreadsheet without showing toolbar.

Reproducing Steps:

1. create a spreadsheet with showContextMenu="true" showToolbar="false"

   	<spreadsheet src="/TestFile2007.xlsx" maxrows="200" maxcolumns="40" width="100%"
   		height="100%" showContextMenu="true" showToolbar="false" />
   

2. right click on a cell. No context menu shows and a javascript occurs as follows:

   Uncaught TypeError: Cannot call method '$contains' of undefined zss.wpd:1973
   zss.FontFamilyCombobox.zk.$extends.setDisabled zss.wpd:1973
   zss.StylePanel.zk.$extends.setDisabled zss.wpd:2847
   zss.SSheetCtrl.zk.$extends.getStyleMenupopup zss.wpd:15142
   zss.SSheetCtrl.zk.$extends.openStyleMenupopup zss.wpd:15227
   zss.SSheetCtrl.zk.$extends.showCellContextMenu zss.wpd:15201
   zss.SSheetCtrl.zk.$extends._doMouseclick zss.wpd:15346
   zss.SSheetCtrl.zk.$extends._doMouserightclick zss.wpd:15128
   zss.Spreadsheet.zk.$extends.doRightClick_ zss.wpd:1157
   zk.Widget.zk.$extends.doRightClick_ zk.wpd:19
   zk.Object.$supers zk.wpd:9
   zul.Widget.zk.$extends.doRightClick_ zk.wpd:30
   zk.Widget.zk.$extends.doRightClick_ zk.wpd:19
   zk.Object.$supers zk.wpd:9
   zul.Widget.zk.$extends.doRightClick_ zk.wpd:30
   zk.Widget.zk.$extends.doRightClick_ zk.wpd:19
   f zk.wpd:21
   jq.keydown.keyup.keypress.bind.bind.zk.currentPointer.(anonymous function) zk.wpd:21
   b.event.handle zk.wpd:8
   bz.handle.bx