If you happen to run into this problem (you cannot resize your windows and have no access to window toolbars) in Ubuntu, the solution is pretty simple. Just run “gtk-window-decorator” (no quotes) from a terminal (or from ALT-F2) and you’re redy to go.

For Unity I read running “unity –reset” (again. no quotes) may help.

EDIT: If this happened in xfce, run “xfwm4 &” from a terminal.