When I open a Calc file there appears a small box labelled "Group" I cannot make entries or close the file only by closing down holding Control and close window

When I open a Calc file there appears a small box labelled “Group” I cannot make entries or close the file only by closing down holding Control and close window.

Does it happen with all Calc files, some or just one? Does it look anything like this:

logroup

Please add information about your operating system and LO version; Help | About and use the Copy icon next to Version Information to copy the needed information.

It happens with all Calc files. A problem maybe unrelated in Writer that text is flickering.T The window which I can’t remove looks exactly like the image in your reply. OS Windows 11, L O version 25.8.2.2 (X 86_64)
Many thanks

What happens if you click on Cancel? Does the box flicker for a moment? If this is the case, your F12 key may have a problem.

The box flickered and the offending frame disappeared, amazing. I’ve clicked cancel lots of times since the problem happened but it never iworked before (Might have pressed F12 as well, not very methodical). I’m so pleased. thank you so much. I have a clue what to do if this arises in future