The executable check does not work for engine or preview commands that
contain arguments, like open -a Preview. Since the defaults are solely
executables the check can be maintained for them, but for an explicitly
set engine the user will probably have knowledge of whether the
engine/previewer can be executed anyway.
The executable check does not work for engine or preview commands that contain arguments, like
open -a Preview
. Since the defaults are solely executables the check can be maintained for them, but for an explicitly set engine the user will probably have knowledge of whether the engine/previewer can be executed anyway.Closes #108