VICE (x64) - Cange the "Custom Keys" of the joystick emulation
the x11 version of vice doesn't give the opportunity to change the keys for the joystick emulation comfortable in its drop-down-menus.
so you have to use the numerals block, the user-defined keys ("custom keys") or to plug in two analog joysticks.
the expression "user-defined" is misleading in this context, because this keys can not be selected anywhere. and so they will be everytime on the numerals block and w,e,r,s,d,f,x,c,v and <space> as fire-button.
but the keyoard-layout inclusive the joystick-keys correspond to a file named x11_sym.vkm, wich can be found in /usr/lib/vice/C64 (most linux variants) or in /usr/local/lib/vice/C64 (e.g. FreeBSD).
example of a joystick mapping:
# # W # | # A-+-S # | # D # # fire : Strg right # w -2 8 a -2 4 s -2 2 d -2 6 Control_R -2 0
i personally like the arrow-keys for joystick 2, so my configuration looks like this: vice_X11_sym.vkm