so, for instance, every time my toggle widget is clicked, the B Folder becomes the selected one:
node.parmTuple("tabs").set((2,)) # exactly like this to pass tuple with one element
elovikov
This one is interesting
So, your first tab is also an implicit parameter, but accessible only by parmTuple. If you set this parameter you can control focus.
Basically, let's say the name of your "A folder" is "tabs" (and you can only change parameter name on the first tab).
Then to control focus you should do something like this:node.parmTuple("tabs").set((2,)) # exactly like this to pass tuple with one element