Firefox&Xwindows question

Is there any way to clear a textbox by say right-clicking it and selecting "Clear" from the menu?

Right now, to delete, I have to select the whole text and press "Backspace" or "Delete" and that destroys my clipboard.

There is no fucking thing as X-Windows. Seriously, you have three different official titles, yet you still manage to pick a wrong one. How does that work?