Steps to replicate would be helpful. What OS? Is there a template on Google Doc where you can replicate the issue and we can also access it?

Hi, OS : WIndows 11 Pro 23H2 build 22631.5039 site  : egprojects.be/echoreunie on the site there is a section : verjaardagskalender ; that's where the google spreadsheet is embedded software used : xara webdesigner thnx

Thanks for the info. You should have Windows Sandbox enabled for testing. https://www.howtogeek.com/399290/how-to-use-windows-10s-new-sandbox-to-safely-test-apps/ I do see the difference using a different browser. see screenshots Someone from Dev will have to chime in.

Yes, I did try other browsers on multiple pc's and all worked fine. Firefox on another pc has the same problem so it's a Firefox problem. Like I said it used to work perfectly in previous versions. Anyway, thank you very much for looking at this ! Much appreciated ....

Guess what, today the problem has dissapeared ..... Calendar works fine, like before. Firefox 137.0.2 (64-bit)