Steps to Reproduce
1. load the attached file
2. click the row heading at row 2 to select the whole row
2. activate the filter
3. select A1:A2
4. click filter dropdown at A2
Current Result
no dropdown appears
Expected Result
the dropdown shows
Debug Information
1. When the bug happens, if you click another non-selected cell's dropdown, it will show.
2. if you select row 1 or select A1:K2, this bug doesn't happen