AC not allowing adding of certain windows as Tabs in Unity UI?

JackAnimated

I want to add the Lighting Window in Unity as a tab next to the Inspector tab. I open the Lighting Window and try to drag the tab next to Inspector, but Unity will only let me Dock the Lighting Window and not add it as a tab to another. Likewise when clicking the 3 dots at the top right of the Inspector window and going to Add Tab, only a few types of Windows are available to add, Lighting not being one of them. Is AC stopping this happening?

ChrisIceBox

Can't see why it would.