Reset the scwmexec protocol. This procedure removes the "XA_SCWMEXEC_REQUEST" property on the root window. It should not be necessary but may be useful in case your X server goes awry (and otherwise you would have to restart your X server). Use if scwmexec or scwmrepl are not returning (e.g., if your Emacs hangs when you try evaluating a scwm expression).