Deleting Rests

I added a bar of 5/4 as the next to last measure of a piece, then entered 5 beats worth of notes. Fine. But after the 5th beat there is a rest that I can't get rid of.

Furthermore, the last measure, which is back to 4/4, includes a dotted half note and a quarter-note rest -- again, fine -- but following that is a 2-beat rest I can't delete. What's the secret? (I would have thought that the number of beats HAD to match the time-signature.) Thanks