silverstripe/silverstripe-framework — pull request #1982 by chillu (2013-05-23 15:55:37+00:00)
Title: BUG GridFieldFilterHeader works without non-filterable cols

Previously relied on the presence of a last column which wasn't filterable,
commonly a GridFieldEditButton. If this wasn't present, the filter buttons
were never added, leading to the GridField JS reload request being sent
without the required button form action, so GridFieldFilterHeader->handleAction()
was never called.

Raising this against 3.0 since I think its a fairly important bug: The UploadField "select file" filtering doesn't work because of it.