Photo Beta sliders are dysfunctional

[PAULRFONTENOT]

After downloading & installing the newest beta version of Photo beta, when trying to adjust background gray levels, the background goes to bright white and then the sliders become dysfunctional.  After the UI sets background levels to bright white, the UI gray level slider ceases to work.  I slide the sliders back and forth but nothing happens

I ran into the same problem in Designer beta (latest version).