:SetEnabled() only has one context currently. That is not to say that it can't be added to a frame for a particular addon for a particular rationale. Excepting the above, as far as I can recall, frames weren't enabled/disabled in that way but rather by :Show(), :Hide(), and the now deprecated :IsVisible() and its replacement :IsShown().
You'd need to drop in the Lua or give us a source-addon for the code to look into it further.