LibreOffice Writer & Calc Find & Replace “Other options” not available

I hope you are well and in good spirits.

I am using LibreOffice 26.2.4.2 on a MacBook Air running on OS 26.6 (Tahoe).

I have often used LibreOffice to re-format data from – for example – a row (or column) in Calc to a block of text in Writer. I then convert the block of text into comma-separated values by using Find & Replace, checking the “Regular expressions” option, and searching for either the end-paragraph expression “$” or the tab expression “t”. The choice depends, of course, on which of these is the separator between numbers.

The Find & Replace option for Regular expressions has become ghosted or greyed out – not available as a selectable item.

Do I need to delete LibreOffice, download the latest version, and re-install it?