Empty Add Media Dialog in post/page editor after update to 3.9

I just updated to 3.9 and when I try to edit any post or page, I can’t add media.

The first time I click the add media button, nothing happens. If I click it again, I get the add media dialog, with all the options on the left-hand side, but no images!

I’ve checked the media library itself and all the images are there.

According to the Javascript console:

Uncaught TypeError: Cannot read property 'show' of undefined load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:593
d.view.AttachmentsBrowser.d.View.extend.updateContent load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:593
d.view.AttachmentsBrowser.d.View.extend.initialize load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:592
b.View load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:5
wp.Backbone.View.Backbone.View.extend.constructor load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:380
d.View.wp.Backbone.View.extend.constructor load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:591
d load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:5
d load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:5
d.view.MediaFrame.Select.d.view.MediaFrame.extend.browseContent load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:591
k load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:5
b.Events.trigger load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:5
d.controller.StateMachine.(anonymous function) load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:591
b.extend.trigger load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:591
b.extend.render load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:591
b.extend.mode load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:591
b.extend.render load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:591
d.controller.State.(anonymous function) load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:591
d.controller.State.Backbone.Model.extend._postActivate load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:591
k load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:5
b.Events.trigger load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:5
b.extend.setState load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:591
wp.media.editor.add load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:594
wp.media.editor.open load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:594
(anonymous function) load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,underscore,backbone,schedule,wp-ajax-r…:594
n.event.dispatch load-scripts.php?c=1&load%5B%5D=jquery-core,jquery-migrate,utils,jquery-ui-core,jquery-ui-widget,jq…:3
r.handle load-scripts.php?c=1&load%5B%5D=jquery-core,jquery-migrate,utils,jquery-ui-core,jquery-ui-widget,jq…:3

Course, I have no idea what any of it means. Help!