Evince renders thumbnails on-the-fly as they get into the scrolling visible area, but at the same time it will remove them as they get out of the visible scrolling area, so when user scrolls back to same position he will notice thumbnails be recreated. In pro of a more icing user experience, let's adopt a mixed approach and keep the thumbnails that the user has already navigated, so when he scrolls back and forth in the same area no thumbnail re-generation will be visible. This also matches behaviour with other pdf readers. https://bugzilla.gnome.org/show_bug.cgi?id=342110 origin commit: https://git.gnome.org/browse/evince/commit/?id=121e4d9