Ritardando Question

In the past, I have added the "ritardando" command the middle of a bar, and it has worked perfectly. The music has slowed gradually until it reached the new tempo (posted in the next measure.) In the past, I have always added this to the top (melody) staff.

Now I am trying to add this command to a rhythm staff. It won't work! The only thing playing are the drums. Why won't they slow down? (Later on in the same score, the ritardando command still works for all the instruments, including drums!)

Well, I found out how to make the ritardando work-- by tricking the computer!

I inserted the "before" tempo just before the retardando, although technically there is no need to do this, because the score is already playing at that speed. Of course, the "after" tempo is inserted right after the ritardando. Now it works!

I think that it always worked before because the tempos always happened to be added within the staff that contained the ritardando. This time, the ritardando appeared within a staff that did not have it's own tempo markings.