_ForgeUser405586 We've encountered a problem using this library with Skada, which is summarized in this ticket In a nutshell, all of Skada's code uses libWindow in the "canonical" fashion (parented to UIParent) and when running in a stand-alone configuration everything works beautifully. However, some UI replacement mods (nUI and possibly ElvUI) like to reparent the Skada window (outside our control), in order to stick it onto their own UI panel. Then later when Skada calls LibWindow to manage position, the library silently assumes UIParent is in use and breaks in horrible ways, eg see comment from lib.SavePosition(): function lib.SavePosition(frame) local parent = frame:GetParent() or nilParent -- No, this won't work very well with frames that aren't parented to nil or UIParent local s = frame:GetScale() local left,top = frame:GetLeft()*s, frame:GetTop()*s local right,bottom = frame:GetRight()*s, frame:GetBottom()*s local pwidth, pheight = parent:GetWidth(), parent:GetHeight() The comment only partially correct - in the case where the parent has been set to nil, :GetLeft(), :GetTop() and GetScale() all return nil (this might be a recent FrameXML change?) and the library subsequently generates a lua error (arithmetic on a nil value). When the parent has been set to a non-nil frame which is not UIParent, the library leads to the frame to jumping around in bizzare ways. Ideally would like to see LibWindow made smart enough to detect when the parent window is NOT UIParent, and behave in an intelligent manner when this baked-in assumption is violated. At the very least it should avoid generating lua errors when the position/scale queries return nil. Better yet, the library would detect the reparenting and stub itself out entirely, under the assumption that some other mod has taken explicit control of position.