Recently I started using a VU meter in the Master bus.  There is an option to dock it in the MultiDock, which I have done.  Unrelated, I have then created a regional FX with Melodyne, and as soon as Melodyne opens, the VU meter is kicked out of the MultiDock.  This has also been the behavior with a couple of other plug-ins that I have docked in MultiDock.  They get kicked out as soon as Melodyne opens.  
 
Is there something I am missing?  Seems like there is some setting that I don't have correct.   In the MultiDock I also have the Browser, Console, and Markers page, which don't get kicked out.  I looked up other threads, but don't really see this issue address.  Or perhaps, it is just one of those things.  
 
Thanks! 

Are they kicked out or is Melodyne opening in a new tab in the Multidock and hiding the VST?

Just checked.  Kicked out.  Melodyne opens, creates a new tab, and  the plug-in disappears. When I close Melodyne, by either bounce to clip or just closing the window, the plug-in is definitely gone. 

right click on the tab (the VST tab) in the multidock and choose "Lock contents".
this might work.
 
It might be a conflict because (Im guessing) its a VST 2 / 32 bit plug in.

When I right click on the VST tab (while in MultiDock), only 2 options come up: 'close' and 'undock.'  Looking in the manual, its says exactly what you suggested Chuck.  And clicking in the upper left of an undocked window should give an option of 'lock contents,' but I get the usual Windows options and options to 'disable Floating,' 'Dock in MultiDock' and 'upsampling.' 
 
And I do have the latest build of Splat 2017,02 build 45.  Seems that the MultiDock is somewhat 'challenged' with my computer.  I don't know if this ever happened in previous builds, as I hadn't ever tried docking plugins before.  

OK! May have found some solution!  If I click on the 'stick pin' icon near the upper right of the VU meter window, enabling the 'pin plugin window,' and then I right click in the title bar, up comes the option to 'dock in multidock.  Now with the 'pin plugin window' enabled and the VU meter in Multidock, Melodyne just makes another tab in the MultiDock and does not kick it out.  
 
I did also uncheck the  'Recycle Plugin Window,' but I am not sure this made any difference.  Further testing will follow......Rechecking the 'Recycle Plugin Window' doesn't seem to affect this.  Melodyne did not kick out the plugin from the MultiDock with the 'pin plugin window' enabled.  
 

@bwbalint
 
Thx, nice find on the stick-pin. It's been this way for at least a couple of releases. It kicks all VSTs out of the multi-dock, not just one.
 
Small note. The stick-pin is -only- visible when opening the VST window to insert it into the multi-dock. It is not visible after the VST has been inserted into the multi-dock (on the ones I've checked). 
 
Not exactly intuitive. 
 
Probably worth an official report unless it's a feature update that I'm not smart enough to figure out?

Being somewhat new to this, how would I put in an official report? Thx!

http://www.cakewalk.com/S...Contact/Problem-Report

Will do. Thx!