Description:
When scrolling through a list slowly with mouse wheel, when you stop, the tooltip for a cell will appear with the contents of the cell. This would normally be useful, but it comes up a lot faster than tooltips usually do, and also sits underneath the cursor.
Sitting underneath the cursor is also an issue because it stops scrolling, so the mouse has to be moved away from its current position. There's a good chance this will invoke the tooltip to appear somewhere else instead.
It's worth mentioning you can (very briefly) see the tooltip for the previous cell when it appears but before it updates to the current cell.
How to repeat:
The first issue.
1. Get a list of results you can scroll through.
2. Scroll a little with your mousewheel while the cursor is on the grid.
3. Stop scrolling
4. Try to scroll again without moving your cursor. Note that because the cursor is being hittested by the tooltip instead of the grid, the scroll is being picked up by the toolip instead.
The second issue.
1. Hover a cell so you see a tooltip.
2. Hover a different cell with obviously different text so you'll see the difference.
3. Observe as the tooltip appears that for a bried moment it appears with the text of the original cell, before updating with the text of the cell you are hovering. The delay may be related to how many rows you have, so for reference I noticed this with 50k rows and 28 columns.
Suggested fix:
Regarding the first issue highlighted, offset the location of the tooltip by a few pixels from it's current locaiton. IE don't start it at the exact position of the cursor. Windows usually does it directly underneath most of the cursor. The default positioning of the Winforms tooltip control is fine, as long as it isn't being offset manually.
For the other issue, simply setting the value of the tooltip before showing it is the simple fix, instead of the other way around.