Custom tuplet entry doesn't seem to work correctly

Hi, I'm running version 2.1.0 and I'm trying to enter a custom tuplet (10 16th notes in the space of a quarter note). Using the approach noted in your handbook ( Notes, Tuplets, 10/4...etc) I get 5 eighth note rests and a 10 over the group of notes. If I try the same procedure to get a 9 16th note tuplet or an 11 16th note tuplet it works as the handbook describes.