When I select more than 100 photos from the grid view, "Revert capture time to original" in the "Metadata" menu becomes active. Why?
I have a vague memory of a previous discussion I can't find: When you click on the menu, LR examines the catalog entry for each selected photo to determine if the photo's capture time has been changed, and if any of the selected photos have had their time changed, the menu won't be greyed out. But when there are a large number of photos selected, this examination of the catalog entries could take a relatively long time, delaying the appearance of the menu. Rather than delaying the appearance of the menu, Adobe decided to not do the greyed-out check when more than 100 photos are selected.