What I want is a scroll box with a 2-layer tree with selectable elements.
--> [+]Category A
--> --> Element 1
--> --> Element 2
--> [+]Category B
--> --> Element 3
--> --> Element 4
--> [+]Category C
--> --> Element 5
--> --> Element 6
But I'm not really sure which of the (3) scroll frame templates that I should be basing stuff off of for creating something like that. The new dual-pane quest log seems to use HybridScrollFrameTemplate. But a lot of other examples use either the Faux template or UIPanelScrollFrameTemplate.
If I understand things correctly:
a) I have my master frame (f) which is the full size of the entire dialog
b) I create a sub-frame (child of f), called "f_scrollframe", covering the area where the scrolling area will appear. Some notes indicate that the width of this doesn't matter, other places seem to indicate that the width should match the area you want covered.
c) I create another frame (regular frame) as a child of the f_scrollframe, and call f_scrollframe:SetScrollChild(f_scrollchild). This frame is what the content actually gets shoved into. So if I wanted to put a tree in, or multi-line text, or a bunch of controls on individual rows, those would be children of the f_scrollchild.
Since I'm not using AceGUI to build my UI, not sure whether I could lean on the TreeGroup widget in AceGUI.