"Basil L. Contovounesios" writes: > Ah, yes, thank you. I forgot about --fg-daemon (which I now remembered > is documented in '(emacs) Initial Options') because it is not mentioned > in the emacs(1) man page; do you think this option should be added there? Oh, yes it should be. >> + if (XFRAME (frame)->output_method == output_x_window Also, I noticed that there is FRAME_X_P for this. I can't find any more obvious instances of missing this check, although it's hard to tell in many cases if the frame is really guaranteed to have output_x_window has the output_method.