It seems like maybe 3 months now since Firefox did the auto download/install of a new version, and ever since the right mouse menu just momentarily flashes on, then disappears. To read the right mouse menu I have to repeatedly run the mouse cursor over the menu until it flickers enough times to read the text, then I have to guess that I have the mouse cursor on top of the correct menu item from where it was flickering before I click it. This problem never occurred in the earlier versions of firefox