elements: Get the main window from the container
mediafilespreviewer: Clarify what parameter the PreviewWidget constructor expects
medialibrary: Move function in the class where it's used
medialibrary: Make sure the comparator for the media library model is strict
ui: Clarify what beautify_info receives
ui: Clarify what parameters info_name accepts
ui: cleanup imports
Show the full pathname in the tooltip for an asset

The file name is already visible, the full path can be useful.