I run Linux, and am used to selecting text with the mouse to copy and pressing shift-Ins to paste. (This uses an alternate clipboard known as the "Primary Selection".)
This seems to work in every app besides Firefox. Firefox uses a different clipboard, where Ctrl-C copies and Ctrl-V pastes. Is there a keystroke or configuration change I can do to make Firefox paste from the Unix "primary selection" clipboard -- the one it pastes from when I click the middle mouse button?
Edit: I'm looking for a keyboard shortcut. Not mouse.