synthesize-event does not work with xterm

[Maurice <mauricex gmx net>]

Hi list,

for example I have the following keybinding to map my
mouse-thumb-button to a key-event:

(bind-keys window-keymap
  "Button6-Click"
        (lambda ()
          (interactive)
          (synthesize-event "M-Left" (input-focus)))

This works fine with mozilla (and I think with any other app too)
but not with an xterm.

Does anybody have a idea?

Thank you


PS: I think this is sawfish-related because the program imwheel does
    this correctly. But imwheel has other problems with sawfish, so I
    tried this.