I've just bought a new MacBook Pro, and transferred my old computer's contents to the new one. Everything works fine except for Mozilla. When I open Mozilla the contents of the window, the URL bar, the tabs and the buttons are tiny. I can zoom in to improve the contents but this does not fix the problem of the tiny URL bar, etc, which are virtually unreadable they are so small. If anyone has any suggestions for fixing this I'd be very grateful to hear them. I've tried reinstalling Firefox; no difference. Screenshot attached.