Unable to dock sub-Windows back into xLights

[cmndr brain]

I've always had the house preview in a small window on the side, inside the main xLights window when I'm sequencing.  When I want to view the sequence, I drag the house preview, hold ctrl and let it sit outside of the xLights window so I can enlarge and watch.  When done, I move the house preview back and it attaches itself back into the xLights window. 
Now, I am unable to snap the house preview back into xLights main window.  It just sits over xLights in its own window.  The only way to get it back within xLights is the change my perspective to the default, then change it back to my saved perspective.  This is the same for the model preview as well.  All of the other sub-windows can be pulled out and embedded back in.
Is this a glitch or a design decision?  Is there a way, keystroke, etc., that can dock the preview windows back in?

(I have pictures, but the site won't let me upload them)

[kenoman742]

In Xlights, go to "View" menu, "Windows", "Suppress Dock", and uncheck "House Preview" and "Model Preview".

[cmndr brain]

Thank you.  I don't know when they added that feature.  Maybe the setting changed when I upgraded the version.
Thank you, that fixed it.

[algerdes]

OMG!  THANK YOU!
I am a long time user, and have hated the automatic docking of windows when moving them around the screen.  Even knowing the Ctrl-drag trick didn't always stop it. (Apparently not holding my tongue just right.)

Didn't have a clue that this "Suppress Dock" was added.

Thank You again.