Docked Window disappeared

Strange issue that occurred today. 8.1.38 Vision.

I have a North and South Docked window.

South window is navigation bar (custom, not tabs) that simply opens windows within docked windows.

Today (not sure when happened) I looked at the client, and the bottom docked window was gone, and the normal window within the docked areas had expanded to fill the bottom area usually occupied by the docked window.

Settings on the docked window are:
Closeable False
Maximizeable False
Resizesble False
Start Maximized False
Dock Position South

Settings on middle window that expanded:
Closeable True
Maximizeable False
Resizeable False
Start Maximized True (wondering about this)
Dock Position Float

Project settings
Axis precedence North/South
Prevent docking overlap True
Infinite Desktop False

All my windows are scaled to native resolution of 1366x768, so no resizing occurs by Ignition.

I have a dozen of these style apps running, and this is the first instance of this occurring. Maybe a glitch, but anything in my settings that could cause this?

Do you have the client menu enabled? A user can close arbitrary windows, including docks, from that.

No sir

Hide Menu Bar True
Hide Windows Menu True

Something likely closed it.

Try adding a log entry via the window closed script on the docked view to see what closes it next time.