Message Tabs Not Showing

I mainly use Chrome and when opening a message the tab is partially hidden by the top bar making it impossible to close it. I occasionally use Firefox which does not have the problem. There were posts some time ago about this and the last I recall stated the problem had been fixed in an update but it appears not. Previously I could get round this by toggling the chat button at the bottom of the left panel but this no longer does the job. It is not a major problem but an annoying one. Is there any progress on this please?