I've been using the OT in NT parallel with Greek texts and parallel English texts. I've saved this as a workspace. It all works very nicely until I close the workspace and reopen it when it looks like the attached image. This happens on both Windows and Mac OSX but the image below is from Win 10.3.0 PR 3.
Minimizing and maximizing the workspace window does not help. Selecting texts from the pull down menu does not help. The only thing I've so far got to work is closing the parallel and opening it again setting up the texts in it again.