Screen Options Tab Not Working

Hi

I’m hoping someone can help me.

Recently (since I updated WordPress) I can no longer use the “Screen Options) or “Help” tabs. They are there, but if I click them, nothing happens.

What does happen, for example, is if I click “screen “options” the “help tab disappears and the arrow points up. As it would if the drop down menu were to appear, but it doesn’t.

I have been in touch with the theme creators, but they have never seen this problem before. There is no mention of it on the support forums and have ruled out that it is theme specific.

I have tried this

and the obvious reverted back to TwentyTwenty and disabling all plugins. Nothing changes.

Can anyone help me? I have no idea how to fix this. And I can’t find any ideas online that would help. Different browsers don’t make a difference either.

Thanks

Lisa