multi-monitor bug? Windows-configurations always fail
 

Have two displays on my macbookpro. I have my markerslist and my windows-configurations-list open. I put my arrangement window on display 1 (which is also primary screen), the video picture on display 2, and the two lists plus an open analyser plugin on the screen of my macbookpro.
I save this as a windows-configuration, I save a memory location with this windows configuration.
I open another one and return to #1 = arrangement is on display 2 in front of the video. display 1 is empty. the lists and the plugin from MBP screen disappeared.
I regroup everything. I save again. I save the session. I restart PT. Display 1 is empty, display 2 is empty, MBP display is empty.

Is this a bug?
What can I do? :o

MacBookPro late 2013, OSX Sierra, PT12.5