I have 2 laptops with the latest MyDMX 2.1 on (Mar 27 2017). Both are Windows 7 Pro. One is 32-bit, one is 64-bit.
Steps to reproduce the issue:
Load ScanLibrary program.
Click one of the header items to edit such as Beams, Type or Lamp Power.
64-bit: The Profile Settings window appears but the contents of the window are not drawn.
32-bit: ScanLibrary program crashes. (Crash report sending fails with internet connection error and suggests reporting "error 99".)
Edit: More info
If you drag the Profile Settings window until it just touches the right side of the screen, the window contents are drawn and are responsive as long as the window is left there. This means that this bug is not a showstopper for me as I can continue to edit fixtures but I suggest if it is repeatable for you, it should be a high priority!