I'm encountring a problem when using grid list filters and buffered store.
when I try to show the filter menu, the following js error occurs : Uncaught TypeError: me.grid.store.collect is not a function

I created this fiddle to illustrate the problem. If you try to filter by ID column or formtitle column, the error occurs. But if you try to filter by title column, it works because the filter on this column is of type string and not list.
If you change the store from bufferedStore to store everything works fine.

It seems that this is a known bug. I found the following discussion that was created more than a year ago but there is no new posts since 5 jan 2015 and the thread still opened !!!

Can you please tell us when this bug will be resolved ?
Or a at least, can you give us a patch to continue using extjs ?