Add Media button bug with WP 4.0

hi
same problem as many people, from what i read on the forum. add media buttons not working anymore since i upgraded to wp4.0
i’ve got none of the plugins mentioned in other similar issues (resolved) that were the cause of that bug. i deactivated my plugins anyway but still it doesn’t work
could it be a problem between wp4.0 and my theme? (propulsion)

as a result it is impossible to upload pictures in a slideshow or in a post yet was ok to upload pictures in the media library directly (but impossible to use them after)
this is what it shows when i click on Add Media (then it does nothing) :
/wp-admin/post.php?post=2995&action=edit#

thanks for your help…