Multiple Vaults Not Stacking in Windows

What I’m trying to do

I currently have three vaults – my main vault and two specialized ones. For a long time, the way they showed up when I had them all open in Windows was as a nested “stack” of windows in the toolbar.

But for months now, for reasons I can’t determine, whichever one opens first stays “solo,” even though when I open the additional vaults, they stack with each other. (I don’t know if there’s a real, official terminology for this.)


Can anyone tell me why it’s doing this? It’s easier to use them when they ALL stack together, because then when you mouse over them, you can see all the options and click to open the right window, whereas if they show up like separate apps, you have to check them all separately. A minor thing, to be sure, but disruptive to the workflow.