Extra windows when using "target=window"

[kasemir]

Close all phoebus instances, then delete memento to get fresh start

rm $HOME/.phoebus/memento

Launch phoebus in 'server' mode.

phoebus.sh -server 9876

Result is the main application window with a 'welcome' panel since nothing else was open.

Now ask that running application to open a display in a new window:

phoebus.sh -server 9876 -resource 'examples:/01_main.bob?target=window'

It does open the resource in a new window, but it also creates another empty window.
That additional empty window cannot be closed.

When asking the running application to open a resource in the existing window, there is no problem, only "target=window" creates an extra, empty window.

phoebus.sh -server 9876 -resource 'examples:/01_main.bob'

Reported by Graham on Windows and Linux, and can also be duplicated on Mac OS.