Spreadsheet selection model and buffered store

Ext version tested:

• Ext 5.1.0 rev 107 and Ext 5.1.1 rev 371

Browser versions tested against:

• Chrome

Description:

• When using the spreadsheet model and having a buffered store there is a problem in onPageAdd().

Steps to reproduce the problem:

• Load fiddle http://ift.tt/1aroyuG

The result that was expected:

• It should work same as with non buffered store.

The result that occurs instead:

• JS error.

Spreadsheet selection model and buffered store