some Alt key combinations don't work under unity

[bgruber]

When running x2go under unity, some alt key combinations register as pressing and releasing alt and then pressing and releasing the other key.

This isn't the case for all alt combinations; i know that, for example, Alt+c works, while Alt+x does not.

Here's xev output for when I hold down alt, press and release x, and then release alt (broken):

KeyPress event, serial 36, synthetic NO, window 0xa00001,
    root 0x6a, subw 0x0, time 2860753128, (60,74), root:(1183,126),
    state 0x0, keycode 64 (keysym 0xffe9, Alt_L), same_screen YES,
    XLookupString gives 0 bytes:
    XmbLookupString gives 0 bytes:
    XFilterEvent returns: False

KeyRelease event, serial 36, synthetic NO, window 0xa00001,
    root 0x6a, subw 0x0, time 2860754717, (60,74), root:(1183,126),
    state 0x8, keycode 64 (keysym 0xffe9, Alt_L), same_screen YES,
    XLookupString gives 0 bytes:
    XFilterEvent returns: False

KeyPress event, serial 36, synthetic NO, window 0xa00001,
    root 0x6a, subw 0x0, time 2860754741, (60,74), root:(1183,126),
    state 0x0, keycode 53 (keysym 0x78, x), same_screen YES,
    XLookupString gives 1 bytes: (78) "x"
    XmbLookupString gives 1 bytes: (78) "x"
    XFilterEvent returns: False

KeyRelease event, serial 36, synthetic NO, window 0xa00001,
    root 0x6a, subw 0x0, time 2860755018, (60,74), root:(1183,126),
    state 0x0, keycode 53 (keysym 0x78, x), same_screen YES,
    XLookupString gives 1 bytes: (78) "x"
    XFilterEvent returns: False

The Alt_L KeyRelease happens as soon as I press down on the x. In constrast, this is what happens when I press Alt+c (not broken):
KeyPress event, serial 36, synthetic NO, window 0xa00001,
    root 0x6a, subw 0xa00002, time 2860925026, (67,41), root:(1190,93),
    state 0x0, keycode 64 (keysym 0xffe9, Alt_L), same_screen YES,
    XLookupString gives 0 bytes:
    XmbLookupString gives 0 bytes:
    XFilterEvent returns: False

KeyPress event, serial 36, synthetic NO, window 0xa00001,
    root 0x6a, subw 0xa00002, time 2860927697, (67,41), root:(1190,93),
    state 0x8, keycode 54 (keysym 0x63, c), same_screen YES,
    XLookupString gives 1 bytes: (63) "c"
    XmbLookupString gives 1 bytes: (63) "c"
    XFilterEvent returns: False

KeyRelease event, serial 36, synthetic NO, window 0xa00001,
    root 0x6a, subw 0xa00002, time 2860928054, (67,41), root:(1190,93),
    state 0x8, keycode 54 (keysym 0x63, c), same_screen YES,
    XLookupString gives 1 bytes: (63) "c"
    XFilterEvent returns: False

KeyRelease event, serial 36, synthetic NO, window 0xa00001,
    root 0x6a, subw 0xa00002, time 2860928315, (67,41), root:(1190,93),
    state 0x8, keycode 64 (keysym 0xffe9, Alt_L), same_screen YES,
    XLookupString gives 0 bytes:
    XFilterEvent returns: False

This worked fine in ubuntu 13.10, and is a new problem in 14.04. I also tried it under a different window manager (awesome) and it worked fine. I'll also note that, in order to get other things to work correctly, I'm running "setxkbmap -model evdev" on the server side.