I've noticed small, but annoying bug in GridTextBoxEditor class.
When one presses F2 to edit cell value, the editor selects all text. This is fine. However, when one presses left arrow to cancel text selection and navigate caret inside the text, editor suddenly closes and grid gains the focus.
It looks that GridTextBoxEditor doesn't take in accout SelectionLength property when decides whether to advance the focus to the grid or not.