Mix console opens but is quite invisible after installing 4.0.1

After installing 4.0.1 I first did not find anymore the mix console.
After some multiply clicking the mix console button, I recognized that the mix console opened, but shrinked to a quite unvisible black bar. See attached picture. This bar can be resized et voilá! The mix console is available. This should not happen anymore in future versions please. Thanks!