FenUI

FenUI is a progressive-enhancement widget layer over Blizzard's frames and templates, with a design-token theme system. The copy in Mechanic/Libs/FenUI/ is synced from the FenUI source repo (_dev_/Libs/FenUI); fix FenUI in its own repo and re-sync rather than patching the vendored copy. Authoritative docs: Mechanic/Libs/FenUI/README.md and Mechanic/Libs/FenUI/AGENTS.md.

Access and degradation

FenUI is a plain global (FenUI = FenUI or {} in Core/FenUI.lua), not a LibStub library. The library is embedded through Libs\FenUI\FenUI.xml. Always guard when FenUI is optional:

if FenUI and FenUI.CreatePanel then
    frame = FenUI:CreatePanel(parent, config)
else
    frame = CreateFrame("Frame", nil, parent, "BackdropTemplate")  -- fallback
end

Factories

Pattern: FenUI:Create<Widget>(parent, config) returns a Blizzard frame with a mixin applied. A string config is accepted by CreatePanel (title) and CreateButton (text). Builder forms exist for a few: FenUI.Panel(parent):title("..."):build(), FenUI.Flex, FenUI.Stack, FenUI.TabGroup, FenUI.Group.