When editing a text grid cell, double-clicking on a word in the edit box should select that word. The word is selected but then the selection immediately clears, so the grid control is interfering with the native behavior of the edit control. This occurs both in FF and IE.
Double-click selection of word while editing grid cell
Problem confirmed and fixed, fix will be available as part of next build.
If you need it ASAP - please contact us directly at firstname.lastname@example.org