I have tried =kde-base/khotkeys-4.8.1 and =kde-base/khotkeys-4.8.2. I can set any button with numbers 2-9 as gesture activation button. But the best for me is button 10 on my logitech perfomance mx. But is doesn't work with khotkeys, so as button 13. Output of xev when pressing it: ButtonPress event, serial 36, synthetic NO, window 0x3800001, root 0x161, subw 0x0, time 49057027, (137,130), root:(1173,907), state 0x10, button 10, same_screen YES ButtonRelease event, serial 36, synthetic NO, window 0x3800001, root 0x161, subw 0x0, time 49057189, (137,130), root:(1173,907), state 0x10, button 10, same_screen YES I can use it as b:10 with xbindkeys. I have applied patch attached to similar bug in bugs.kde.org (link in URL field) modified to allow also button number 13 but still no effect to 10 and 13 buttons (they are saved in khotkeysrc but I can't use any gesture with them), only button 1 begin to work as gesture button if I've chosen it.
It make no sense to track this issue forever. From distribution point of view its a minor issue which will not block stabilization. Its reported upstream so maybe someone of the kde devs will pick this issue up in the future.
