Can't delete rests
After importing a MIDI file into Musescore, I found a few problems. I was able to correct those problems in Musescore, except for one. The entire score is festooned with extraneous rests. Some rests are even superimposed on notes, making the notes difficult to read. I found that I can't delete most of the rests. In the attached example, I cannot delete the dotted quarter rest and the eighth rest in the second measure. Presumably, those rests are there to show that there are four beats preceding the quarter note G4 at the end of the measure. I think the rests are unnecessary because there is nothing after the quarter note, and a quarter note is two beats in 6/8 meter, so obviously it occurs on beat 5. If I select the dotted quarter rest, it turns blue, but when I press the delete key, nothing happens. How can I delete rests that appear to be unnecessary?