In trying to test out the reporting module UI this weekend, I ran into a bug in which the date pickers do not appear when using Chrome on Ubuntu 14.04.
If I use Firefox, things work.
If I use Chrome on a Mac, things work.
What appears to be happening is that the class "ui-helper-hidden-accessible" is on the "ui-datepicker-div" element, and this is what is causing the calendar pop-up to stay hidden. I don't know why this is happening.
This probably isn't a show-stopper, but I would like to get this fixed before releasing 0.9.9.