Some odd behavior with the launcher is observed when enabling/disabling the display driver. With the launcher running and the launcher window open and displaying on the desktop, I disable the display driver and the battle.net launcher works fine. If I then enable the driver, sometimes the launcher will hang and be closed by Windows or just crash from an access violation. Sometimes it doesn’t and works fine, but if I close the window, it shows up on the taskbar, but doesn’t draw a window.
Could also be a Windows bug because the Start menu behaves similarly with regard to not drawing, but explorer doesn’t crash. I haven’t experienced this issue with any other program.