Ctrl keyboard shortcuts do not work if text elements on a web page have focus. In such a case you first need to set focus outside such a text element to make the Ctrl key work. Alt should work in text elements, but Alt and Ctrl won't work if a plugin has focus.

Well, that's not the case here. I tried to focus on text field, and the keyboard shortcuts does work, so that's obviously not the case here.

Sometimes the address bar is selected and i can write there, but when the mouse go over the top title, it suddenly stops reacting. And the Alt+D and Ctrl+T are not working doesn't matter if a text field is selected.

BTW, sometimes it does work, it almost seems like an intermittent problem.

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the add-ons is causing the problem (switch to the DEFAULT theme: Tools > Add-ons > Themes).

• Don't make any changes on the Safe mode start window.

See:

• Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems