Calc single sheet frozen and unresponsive with row header 23 hi-lighted

I have LibreOffice calc version (x64) and I have one sheet frozen (totally unresponsive) while all other sheets are working.
The only symptom, apart from nothing working, is that the header for row 32 is hi-lighted and remains so even after save>exit>open

As I have a lot of data already entered on that sheet I’d be much obliged if somebody can tell me if there’s a way to unfreeze the sheet.

Nothing to tell without seeing the document.

Hello @casitasme, What reference is in the Name Box?

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Hello erACK and LeroyG
I didn’t want to post the file as it was too personal but I managed to fix the problem.
I copied the file to an earlier version of calc and got the message that this sheet was locked. TOOLS>PROTECT DOCUMENT>SHEET had been enabled and disabling fixed the problem.
I see that the path to this varies between versions but proceeding along the lines TOOLS>PROTECT ought to find the trouble.
Thanks for responding.