bug: dropdown box in text comparison no longer works

I just noticed that when I click on the version box in Text Comparison, a dropdown list appears, but none of the selections "stick".  You can to type in the versions you want to compare, and then click on the arrow in order to change the versions you want to compare.   Has this been a problem for some time, or is this new to the beta program.  I tested it on both Beta 5 and Beta 7.