DataGrid generates runtime errors when you delete rows in a particular order

[philip]

I found that if you delete grid items in a particular order, you can get Javascript errors. Firebug reports the error as,

this._by_idx[_4bf] is undefined

I think this is coming from the _onDelete method of DataGrid?. I'm attaching a test case that shows the error. A grid with 2 rows is created. When you click on the checkbox, the row is deleted. If you delete the second row and then the first row, you get an error. If you do it in the other direction, everything is fine.

[philip]

Example that shows DataGrid? deletion bug.

[Chris Mitchell]

not blocker for 1.7rc1, lowering priority

[Evan]

In [29251]:

Fixes #11572 !strict, do not apply edit if the row does not exist anymore, also back port to 1.7.x branch

[Evan]

In [29290]:

Refs #11572 !strict, fix regression, a better way to check cell node