Media Explorer stays Docked when re-opened.

[vanhaze]

Dear all,

I experience something weird:

I have Media Explorer undocked.
I have assigned a keycommand for the Action: Media explorer: Show/hide media explorer

This is what happens:

a) Media Explorer is opened as floating window (so undocked).
b) i switch to a made windowset, only containing Main View: Media Exporer closes.
c) I hit the keycommand for Media explorer: Show/hide media explorer.
Outcome:
Media Explorer is opened but docked (to the right side of screen).

I want to have it opened floating again, not docked.
Is there some setting i am overseeing or does this look like a bug ?

Reaper 5.60pre4
OSX 10.12.6

Warm Regards.