Stimulus disappearing bug?

I’m having problems with stimuli disappearing from the screen on their own despite there being no response or predetermined display interval. The behaviour is not consistent but is reproducible.

In the attached example five words are displayed on the screen, one at a time, at different locations until all five are displayed. The screen is then cleared and a message is displayed saying “Press a key”. Pressing a key repeats a similar set of events.

In my tests at least one run in every five has a bug where the “Press a key text” disappears after about a second, leaving the screen blank until the key is pressed. I have also noticed on rare occasions that the display of the five words flickers and the timing of display looks wrong.

This is not a real experiment just a simplified mock up to demonstrate the issue.

Can anyone shed any light on this?

Test.sl5 (5.76 KB)

This may be a bug that shows up as a “white box” on the screen. The thread below has a few workarounds to help you with this issue:

Thanks Monika. Changing to Windows 7 basic theme seems to prevent this issue.

I would say that we have experienced this issue widely in many programs that we (and our students) have produced recently. Hopefully you can provide an update soon to address the bug.

We have not been able to duplicate this issue reliably in-house. Elusive issues like this are hard to fix, but we will address it as soon as we are able to duplicate it.