Highlight: find one fixture in the rig
Which one is Spot 7? The lamp button on its patch row holds it at full so you can see it on stage.
Every row in the Patch list has a lamp button on the right. Press it and that fixture goes to full intensity until you press it again.
It beats everything: the offline preview level, and a desk connected through the Bridge, including a shutter the desk holds closed. A fixture parked out is exactly the one you cannot find.
Several at once is normal. Search the patch list, then press Highlight beside the result count to light every match.
It stays on until you turn it off. Whenever any fixture is highlighted, the panel shows N highlighted with a way to clear them all, so three lights stuck at full do not look like a bug.
It is not saved and not shared. It is a question you ask right now, not a property of the scene. Colleagues and clients do not see it, and opening another scene clears it.
It is not selection. It survives clicking elsewhere, and selecting a fixture does not light it.