The bug is very strange so I do my best to describe it.

I have a grid with two combobox editors in the columns.

To add a new row, I use

PHP Code:
this.getBenutzerView ().getStore ().insert (0, new User ({
   ....
   }));
grid.getPlugin ('myRowEditingID').startEdit (00); 
When I hit update, the request is send to the server but I get a null pointer exception in Ext.view.Table.updateColumns at

PHP Code:
Ext.fly(oldCell).syncContent(newCell); 
because oldCell is null. In fact when investigating the DOM tree behind the RowEditing bar, the columns which uses a combobox are missing (no tds) when the exception rises.

I added a check here

PHP Code:
if (!oldCell || !newCell) continue; 
and it seems to work fine then. After the RowEditing bar closes the dom is intact again.

I haven't tested it with older versions.

Cheers,
Jörn