Ok. I think I see what you are talking about, and I get the same issue that you are talking about.
If I already have a formula in a cell, and I click on the top part of the spreadsheet (to edit the formula), the mouse does not work.
Example: My current formula in Cell G21 reads
"=SUM(C6:C51)"
Now, if I click on cell G21, and then put the mouse at the top bar (to edit it), and I take away the C51), so I am left with
"=SUM(C6:"
I then want to use the mouse again to edit it (just like I did to create it). No matter what I do, while I'm in "edit" mode in the top bar, the scroll on the mouse does not work. I can click anywhere in the spreadsheet, and then use the arrow keys / shift key / ctrl key to select specific cells.
So, I DO have that problem!
However, if you press F2 (to edit the formula in line), then the scroll wheel of the mouse does work as expected.
It appears it has to do with the edit being done in the edit bar at the top.
--Brian