Time Signature Change

When I try to insert a time signature change (from 9/8 to 9/16) the measure with the 9/16 time change and on doesn't have enough rests or notes for 9 16 notes...What I'm doing is going to create-->time signature, then when the window pops up, I change the first top number to 9 and the bottom number to 16. Then I click add. I take the newly added 9/16 time signature from the box and drag it to the measure I want to start the time change.