VDisplayRunModeCommand - displays a switch in the button window that lets
one put processes in the background/foreground.
VDisplayRunModeCommand displays a switch in the button window that lets
one put processes in the background/foreground. The default value of the
switch is FG (foreground). To change the switch value, it is necessary to
call VCheckEventsInButtonWindow. The switch created by VDisplayRunModeCommand
can be deleted by calling VEraseRunModeCommand.
0 - work successfully.
1 - memory allocation error.
VCreateColormap should be called earlier, else VDisplayRunModeCommand prints
an error message to the standard error stream, produces a core dump file
and exits from the current process.