To reproduce this:
- Set the ShowToolTipOnTrimmedText property of RadGridView to True.
- Hover a cell with trimmed text.
- Before the tooltip shows, move the mouse quickly, outside of the RadGridView control.
- Regardless of the fact that the mouse cursor is outside of the RadGridView control, the tooltip showing is not canceled and it shows after a second.
To resolve this, set the ShowToolTipOnTrimmedText of the gridview columns instead of the RadGridView control.