I need help adding drum beats to a pattern I created

I am setting up a drum pattern using the inline editing and using the draw tool to put the beats on the timeline. Once I have put some beats on, when I try to add more beats in between the ones that are already there, it moves the beat to the right over instead of putting a new one in, so I have to keep moving them over if I want to keep what I already had. How do I get it to add beats in without moving others?