I though I already opened a bug for this, but I cant retrieve it, so maybe not.
It'd be nice to have in xfwm some shortcuts to "expand window until the next edge".
Openbox has shortcuts like this, for all directions.
If you use "expand-left", it'll expand the current window to the left, until the next window is reached, or the screen edge. Same thing for other directions.
It's a feature I currently miss and would be glad to have :)
Cheers and thanks for the work!
This is now implemented with the “Fill” shortcuts.