The chasing is just his way of trying to get her to play with him. Lex and April now take turns chasing each other...she even taunts him so he can chase her. At times she climbs up on the sofa just out of his reach and will reach down and swat him on the head and run back and forth on the sofa to get him to chase her. I am going to check previous posts and get the pictures of them playing so you can see.
Here is the link to that post where I put up pictures of them playing...it's the last post on that thread.
http://www.yorkietalk.com/forums/sho...t=royal+rumble