Created attachment 102745 [details]
Preview not working for font size
Preview not working for font size in spreadsheet
If I understand correct, you want Calc to show the font size changing/preview while you are choose different font size from the drop-down list.
I know MSO has this feature, but LibreOffice does not. In fact, in Calc you can preview while you are changing font family, but this does not work when you are chaning font size.
Set to NEW.
Adding needsUXEval as there were other bugs which were refused as far as I can remember.
Live update of the cell when hovering over the expanded dropdown makes not much sense. It's still a classic control. But we could do the same as with font names and show the size WYSIWYG in the dropdown itself, ideally combined with the font name. OTOH, this works only up to some value, has accessibility issues for small values, and in the end I believe it's not worth all the fuzz. My take: WFM.
No further input so let's close this issue as WF (WYSIWYG font size is not possible, life preview is not the LibreOffice way).