Text stimulus blanks out

I recently bought superlab 5 but have been using experiments made on superlab 4. One event on one experiment continually blanks out the text stimulus. Only the middle of the screen goes white with the words on the far left and right of the screen still visible. This never happened when I opened it with superlab 4. I have checked all the settings and cannot find where the issue may lie. Any help would be greatly appreciated!

This is a bug within SuperLab, which was also present in SuperLab 4.5. Below is a forum thread that describes ways to fix the white box problem.