Video Driver Selection.
On a system with more than one display device TimeDX must be told which display is to be used for testing purposes. This selection will determine which display DMDX uses for the experimenter's display and which display to use for the subject (unless DMDX is run with the command line override switch -display).
Getting a multi monitor system up and going used to be something special,
these days you just plug the monitors in and extend your desktop to the new
monitor. However I would note that TimeDX tests done on multimon systems
are best dismissed with a key press as opposed to a mouse click as that mouse
click can change the window focus unexpectedly...
Under TimeDX and DMDX 1 it was recommended that a secondary display not
be part of the desktop, that no longer applies. On the contrary, all my testing has been with them as part of the desktop and after seeing what one of Ken's machines did when the secondary display was not part of the desktop you
must extend the desktop onto the secondary display for DMDX to correctly function (otherwise both displays will tend to be painted white after a job runs).
Fortunately this appears to be the default option these days.
One problem has been bought to my attention and it was on a laptop that could have a second monitor plugged into it. The problem was that on running
TimeDX for the first time you get a choice of video drivers, the selected item being number 2 which is the external (but not activated) monitor. Subsequently running
TimeDX produced an error. Attaching an external monitor and activating this allowed the video driver to be reset but without one the problem was not readily solvable as TimeDX would crash every time it was run. I have since added a command line switch to force the selection of the primary video drivers, -deviceoverride, and I have also changed TimeDX to pick the first driver in the list by default as it appears to be safer than the last driver.