cannot copy with ctrl+c when the toolbar is hidden

Steps to Reproduce

1. load a blank book
<spreadsheet id="ss" width="100%" vflex="1" src="/WEB-INF/books/blank.xlsx"
maxVisibleColumns="24" maxVisibleRows="40" />
2. select A1
3. press ctrl+c

Current Result

zss.wpd:13910 Uncaught TypeError: Cannot read property '$contains' of undefined
at init.afterKeyDown_ (zss.wpd:13910)
at init.doKeyDown_ (zk.wpd:37557)
at init.$supers (zk.wpd:12982)
at init.doKeyDown_ (zss.wpd:13882)
at init.doKeyDown_ (zss.wpd:23036)
at _doEvt (zk.wpd:26479)
at HTMLDocument.<anonymous> (zk.wpd:26572)
at HTMLDocument.dispatch (zk.wpd:5410)
at HTMLDocument.elemData.handle (zk.wpd:5062)

Expected Result

A1 is copied

Debug Information

• if showToolbar="true", this bug doesn't happen.