Unable to edit styles in Calc

I need to define some custom styles in calc to be used in conditional formatting

I can successfully create a new style from the selection e.g. Default Cell Style and then edit that new style immediately but then I am subsequently unable to make any changes to my new style.

Going to the style navigator I am offered a Modify option on the Right Click menu but when I click that nothing happens

Am I missing something or is there a bug?

I have just updated to
LO version
Running on W10

Please upload an ODF type sample file here.

Unfortunately the spreadsheet in question contains sensitive data so I am unable to post it.

Since posting I have tested the basic operation on version 6 and 7 and both work with a simple test as expected. It appears therefore that there is something on my main spreadsheet that is causing the issue. It contains 7 Tabs and about 10 conditional formulae all using styles. I am somewhat puzzled as to how I can further diagnose the problem. I am quite experienced with Excel and LO (Excel since 1989) but this is a new problem.to me.

It is quite likely that it has been opened in Excel at time time in the past,if that is relevant.

@jcs94782, Was the file created in LibreOffice?

jcs94782, delete all of sensitive data from a COPY of your document. The created and applied styles are relevant only.

I did initially create the file in LibreOffice calc but initially wanted it to be capable of being opened in Excel. I certainly have opened it in Excel. Since then I am using a hyperlink to crate an email and the Excel version does not work properly. Excel only passes 255 characters to the email client!

I can strip out all data but I cannot see how to upload it here,

@jcs94782, ,

Edit your question and with the clip icon, use to add the file.

Is there any sheet protected?
If any of the sheets in your spreadsheet is protected, modifying styles is prohibited without any notice.

That is almost certainly the reason. Yes there are several protected sheets within the spreadsheet.

I am unable to test as I have since handed over the spreadsheet to another club member and no longer maintain it. I believe he is using Excel rather than LibreOffice. The spreadsheet contains club membership data and anonymising it would have been time consuming.

Thanks for providing this answer.