Sometimes PLEditor's text is hidden by the gutter. I was not able to reproduce it but it happens from time to time. I don't know if this is going to be fixed in the new beta.
But, I found another way of reproducing the problem.
If you press Ctrl key and roll the mouse wheel the size of text shrinks and expands. When you shrink, the text goes below the gutter area.
I hope this helps finding bug in PLEditor.