In Prefs / Layouts... I click on a test layout... and then click in the box that says: Close all existing listers when loading this layout. I then click Apply and OK and then exit.
But when Opus opens the layout I want, it doesn't close the existing layout.
When I go back into Settings / Prefs / Layouts.. the Close all existing listers when loading this layout is magically unchecked again for the test layout. It won't stick.
What am I doing wrong? Thx.
The most likely thing is some antivirus/privacy software is blocking writes to the XML config file which stores the layout. We've seen it happen before, and some of that software seems to trigger based on file types or file contents, while not telling you it is breaking things when it blocks operations.
I disabled Microsoft Security Essentials, which is the only antivirus app I have.. but still having the same issues. Dopus is still opening other listers without closing the existing lister. I went into Prefs/Layouts again, and almost all of my layouts now have the checkbox un-ticked for the Close all existing listers when loading this layout option.
Is there a setting elsewhere within Dopus that could be interfering or overriding this?
Also, what and where exactly is this file? I`m on Windows 7 64bit. Thanks.
MSE/Defender may need to be disabled in two different places, which can complicate things, although I don't know if it was the same back on Windows 7. Problems caused by Windows Defender (strange behavior when using Opus) has details (but is written for Windows 10).
You can override the flags when opening layouts, but you'd have to do that specifically in the command that was using the layouts, and it wouldn't change what you see in Preferences.
Type /dopusdata\Layouts into the path field and you'll see all the saved layouts.
The timestamp on the edited layout should change if you change a flag on it and click OK or Apply in Preferences.
< SOLVED! >
I tried everything you noted above.. to no avail. Anytime I created a new layout and recalled it from the Layouts drop-down in my toolbar, it didn`t close the existing layout. Each layout I opened kept opening more layouts without closing any of the existing/previous layouts. Grrr...
So I instead added Prefs LAYOUT "LayoutName#1" LAYOUTCLOSELISTERS=yes to several buttons on the toolbar. Anytime I click any of the buttons, the corresponding layout opens and the existing layout closes. Beautiful! It`s all I wanted all along, and since I prefer the Layout Drop-down method to save space across my toolbar.. I then put all these buttons/layouts into a single New Menu button on the toolbar, and all my layouts are now in a drop-down list and working flawlessly! 
Not sure how I didn`t think of simply adding a menu drop-down earlier. Bloody hell..
Anyway, thanks for your help! Dopus rocks!
You shouldn't need to do that. It'd be interesting to know if you can save or update layouts in general. If something is making those files (and/or other config files) effectively read-only then it'll cause other problems.
OTOH, if it works it works.