I have an update but have not had time to troubleshoot and try to reproduce it yet. All of my addons are up-to-date!
IIfa persistent window:
Using "/script d(moc():GetName())" while hovering my pointer over it I get: GuiRoot
Leo's Dolmen Runner:
Using "/script d(moc():GetName())" while hovering my pointer over the empty UI space I get: GuiRoot
Using "/script d(moc():GetName())" while hovering my pointer over the LDR UI space in the upper right I get: LeoDolmenRunnerWindowPanel