Little Error Found, Filling measure with slashes that had repeat marks, then pressing "delete" provides a blank measure. Rests are invisible.
I accidently came across this and it seems like an error.
I filled measures with repeat marks, then I realized I wanted it to be filled with slashes instead. So I filled the measure that had the repeat mark with slashes. Later on, I wanted to have a rest in this measure, so I deleted one (or all) of the slashes, and no rest is shown. When trying to enter a rest in this measure it shows nothing.
In order to fix this, I had to fill the measure with a repeat mark again and THEN hit "delete" to provide a full measure rest.