Pardon me if I missed something in the help document that addresses my idea but I looked and searched extensively.
In the Lister display, I would like to be able to denote that a folder is empty. I know that I could see that condition if I do "Calculate Folder Sizes" but I don't want to have that delay or the associated disk thrashing. I'm imagining that the color of the icon/filename could be changed when a folder is empty, much line the "Set Label" context menu function. But I don't want to have to click a button; I would like it to be automatically enabled unless turned off.
This will highlight folders which are either empty or only contain other empty folders or 0 byte files:
You can't tell if a folder is empty without looking inside of it, so there will always be some disk access caused by any method of highlighting empty folders. The disk access will stop once the first non-empty file is found in each folder, however, so it will be less than is caused by automatic size calculation.
You might also want to add the label to a Folder Format, rather than the global labels, if you only need this in particular locations. Then you only get the extra disk access where you really want it.