Rendered Features Disappear when Columns are Sorted

[geographika]

There is a TOFIX comment in feature-grid/create.md:

* Note: If you sort on a column, some rendered features might disappear
from the grid. This is a known issue, and a solution to this is very welcome.

There is already an issue in GeoExt - geoext/geoext#266 - but might be worth keeping here also as a reminder.