The problem occures, when I switch to fullscreen mode with a widescreen movie then the movie is streched form top to the bottom of the screen with left and right side cut off. When I press the "O" key then it goes to the right state: nothing cut off, and the black area at the top and bottom.

But how to make the player switch directly to the right state when I press the "F"-fullscree key, without always having to press the "O" key on the keyboard?

Thanks in advance.