I've discovered that docked windows aren't keep together when the windowshade mode is toggled.
In the original window distribution (main windows-equalizer-playlist), when you enable windowshade mode for the equalizer, the playlist editor is detached from the others.
It's even worse when you have the three items shrinked and docked on the taskbar. When you disable the windowshade mode for any of them they expand downwards, and the content remains beyond the screen, instead of the desired result: still docked on the taskbar and the other windows pushed upwards.