Flipbook render and 'go to' problem

The timeline on the bottom of the Flipbook view mode today did not allow me to click on the latest date. The latest date I could choose was April 30th.

Edit: It might have to do with the fact that the little orange triangel seems to collide with the vertical bar on April 30th. See it here:

http://www.dipity.com/user/merz1/time...