I have a window, for example an xterm, and I maximize it horizontally using Alt+F7. I go out of xfce saving the session. When entering again on xfce, the session-plugin restores my horizontally maximized xterm, but it is impossible to resize it again to the original size because xfwm4 believes that this (the horizontally maximized size) is the usual size of the xterm.

I guess xfwm4 or session-plugin does not save the original size of xterm and it does not know that it is in a maximized state.