It's a really annoying bug, which occurs only in QtWebkit.

When i press a key (letters only) on the keybard, it does :

Press the good Key
Press "Left key"
Release "Left key"
Press "Backspace"
Release "Backspace"
Press "Right Key"
Release "Right Key"
Release the good Key

Very very strange. I'm working on a bad and ugly workaround (consider backspace key is pressed only if no other key was pressed before and not released)