Please, please, please can you remove the feature that allows a double layer of marking photographs in Lightroom. When you mark one photograph and delete it from disc it deletes the second level marked files too (without warning you). This is a disaster as you cannot undo the delete (why not?) and you have to restore the files from the recycle bin. All edits are lost on the photos. I have done this by mistake 3 times now causing me about four days of work.