One feature of Linux Mint 17 that doesn’t function particularly well is pressing the Menu button on the panel. Nothing happens. Well, nothing happens for a while. The menu is extremely slow to appear. This is a known issue and, fortunately, it only affects the first time the menu is called up. If the button is pressed on subsequent occasions, the menu instantly snaps into view, as one would expect.
Menu is slow to appear, misses keypresses #315