Generating Thumbnails : No more visual information.

When the medialibrary scan is ended, the thumbnails are generating, or at least for the videos that you see on your current screen.

But if you have a lot of videos, and you quick go down to your list, thumbnails are missing because the generation is still in progress, and there is no information for that.

We should have something, like a notification information that the thumbnails generation is in progress, because that could be misinterpreted to be an issue.