How can I hide the blue progress bar on opening a new lightbox?
It's flashing. Flashing is bad. #uxMatters
Topic on Extension talk:MultimediaViewer
What do you mean by flashing?
It appears after the page is rendered and disappears again after a few milli seconds. That's annoying.
That sounds wrong. Could you file a bug with specifics (which page/file, did you view other files on the page before viewing)?
In any case you can hide it with .mw-mmv-progress { display: none; }