I tested, and I came up with a few interesting observations.
- In the ribbon, go to the developer tab. Make sure that the Design
Mode is not on.
- When I first froze panes on the sheet, the freeze line went through the listbox I created. This caused the behavior you are describing with the cross-hairs and being unable to select.
- Then I moved the listbox. Still same problem. I tried clicking on various cells around the sheet and in the ribbon area, with no change in behavior.
- When I clicked to another sheet and back again, it started working as expected. Normal pointer mouse. I could select multiple, and unselect as needed.
Based on what I've tried, it seems that making sure Design Mode is off, and clicking to another sheet and back again may fix the problem.