The problem with "Create thumbs for whole folder"=ON is that many times it simply takes too long to create thumbs in an uncached folder. MP just sits there making thumbs from the top down, and scrolling down through the thumb panel doesn't restart the thumbs creation at the new scroll position. The folder is essentially useless until it has been completely "thumbed".
The problem with "Create thumbs for whole folder"=OFF is that it doesn't always work.
With that setting, most (but not all) of the time when the user scrolls down in the thumb panel, thumbs creation resumes at the new place. I think that is the intended behavior.
But using the filter or performing a file action that changes the population of files in the folder can halt the thumbing activity and MP may just sit there doing nothing. This is particularly a problem when there are too few thumbs to fill the thumb panel. One frequently has to navigate OUT of the folder and then return to reset/restart the thumbing activity.
IMO it really makes no sense for the toggle "Create thumbs for whole folder" = OFF and "Create thumbs for whole folder"=ON to apply equally to cached thumbs as well as uncached thumbs.
Here would be a good behavior for my use:
- - Always display cached thumbs for the currently visible set of files/folders FIRST.
- THEN, display all cached thumbs in the entire folder
- THEN, create thumbs for all images in the folder before thumbing the sub-folders (a user toggle for this behavior would be welcome).
- When thumbing image files, create the thumbs in file size order (regardless of the current sort order), small files first, then large files. This should fill the thumb panel to a more usable degree than currently (where the thumbs are apparently created in the current sort order).
One final thing: thumbnail creation performance should be tested on the slowest drive a user would reasonably be expected to employ. Perhaps an USB 1.1 thumb drive would be a good place to test. I don't use such a thing anymore, but if the thumbing process was optimized for a slow disk environment, it would "fly" in the more common faster ones.