Hi, Everyone.
I’m trying to clean up lip sync on my character’s mouth layer and need to be able to extend a given mouth for a few frames by dragging on the timeline. I know I did this on a previous animation, but now when I click on the last frame of the mouth I want to extend – and drag it to the right in an attempt to extend it a few more frames – nothing really happens. Each cell that I drag over turns yellow (one after the other), and a little gray rectangle appears beneath my cursor, but I don’t get the desired result.
Can anyone offer any tips?
At the moment, my “workaround” is to right click on the cell I want to extend, select “Extend Exposure”, and manually enter the frame number to which I want it extended. Needless to say, I’m looking for something quicker. 
Thanks so much!