Thank you for helping me to realize that Gain amount was a link to click. I had not noticed that.
I do think it would be better if the amount of storage space for each item was listed next to the item. For example:
[ ] Windows Update Cleanup (1.13 GB)
[ ] Temporary Internet Files (111.3 MB)
[ ] Thumbnails (342.1 MB)
Or maybe it is best to list the number of files too:
[ ] Windows Update Cleanup (653 files, 1.13 GB)
[ ] Temporary Internet Files (191 files, 111.3 MB)
[ ] Thumbnails (40 files, 342.1 MB)
The Preview window works okay, but I don't think it as easy for the user because you do have to look for each item in the Preview or go back to the left side (listing with checkboxes) and check the items you decide to "cleanup". This is an inconvenience for me because I usually use the storage amount estimate to aid in deciding what I am going to cleanup. It doesn't really matter if I am going to clean certain items without concern for the storage space amount that will be gained. I hope that makes sense.
Currently, there are missing items in the Preview. Notice in my screenshot that Previous Windows Installation(s), DNS Cache, Print Queue, and other items are not listed in the Preview window. Everything on the left side (with checkboxes) should be listed in the Preview. If you cannot calculate the amount of storage space to be freed/gained, then you should say "Preview was skipped for performance reasons" or something.
Another problem with this current implementation is the Preview does not show any "Gain" estimate for "+ more" items (Google Chrome Cache, Microsoft Edge Cache, etc.) It would be good to know how much storage space these items are using and one might then decide to go ahead and "cleanup" some of these.
Thank you very much for all of your work and time on Cleanmgr+. Please do not let my constructive criticism discourage you. I simply want Cleanmgr+ to be the best for me and everyone else and I want to use it. I will gladly donate some money as well, especially once the program is a bit more polished.
Have a great remaining weekend.