Steps to Reproduce

1. load attached file
2. set network throttling to Fast 3G to simulate longer latency
3. select 4th sheet
4. select 5th sheet
5. repeat selecting 2 sheets interchangeably, before one sheet renders completely select another sheet

Current Result

>zk.wpd:20638 Uncaught TypeError: Cannot read property 'text' of undefined
at init.$init (zss.wpd:6513)
at new init (zk.wpd:9850)
at init.$init (zss.wpd:5771)
at new init (zk.wpd:9850)
at init.doSheetSelected (zss.wpd:17487)
at init.sheetId (zss.wpd:575)
at init.setSheetId (zk.wpd:9889)
at Function._set2 (zk.wpd:10333)
at init.setter.func (zk.wpd:15882)
at init.zk.Widget.zk.$extends.set (zk.wpd:15910)

Expected Result

no error

Workaround

select sheets slower