compose key doesn't work and types "⁉" character instead

works fine in qt4 and tk
xev:

KeyPress event, serial 34, synthetic NO, window 0x5800001,
root 0x98, subw 0x0, time 51287731, (695,21), root:(696,422),
state 0x0, keycode 105 (keysym 0xff20, Multi_key), same_screen YES,
XLookupString gives 0 bytes:
XmbLookupString gives 0 bytes:
XFilterEvent returns: True

KeyRelease event, serial 34, synthetic NO, window 0x5800001,
root 0x98, subw 0x0, time 51287809, (695,21), root:(696,422),
state 0x0, keycode 105 (keysym 0xff20, Multi_key), same_screen YES,
XLookupString gives 0 bytes:
XFilterEvent returns: False