Kaspars, thanks for addressing the problem here. :)
Everyone else, I'm having what I believe to be the exact same problem as all of you. I've been providing Kaspars with info related to the problem, but I don't know that any of it has gotten us anywhere yet, aside from being more conscious that the problem exists. ;) If anyone could pitch in with any additional info or troubleshooting, I'm sure that'd be helpful!
I really appreciate this plugin and would love to help get it working properly for me, regardless of what the problem is! I'll certainly keep troubleshooting on my end and report back if I figure anything out. If everyone starts providing info perhaps we can find a common thread in our installations that is causing this problem.
For informational purposes:
The plugin is working perfectly for me from the Gallery tab, and doing exactly what it's supposed to. The problem I'm experiencing is that when it is enabled, the Media Library tab does not function properly on any page or post. The image thumbnails do not display, and the "Show" link does nothing at all. This affects inserting individual images. (It should be noted that for some reason everything behaves correctly if the HTML editor is selected, rather than the WYSIWYG editor. That said, I'm not comfortable telling a client to just "deal with it" if they are not comfortable with the HTML editor.)
I receive an error in the JS console when I click on the Media Library tab.
In Chrome the error reports as:
Uncaught TypeError: Cannot set property 'checked' of null
In Firefox the error reports as:
f.I("linkto-file") is null @ http://[removed].com/wp-admin/load-scripts.php?c=1&load=jquery,utils,swfupload-all,swfupload-handlers,json2,thickbox,media-upload,jquery-ui-core,jquery-ui-widget,jquery-ui-mouse,jquery-ui-sortable,admin-gallery&ver=602c76d06172ee798ff8b58597fbb1dd:471
If I deactivate Multiple Galleries I do not get this error and the Media Library tab exhibits proper default behavior.
I'm running a fresh install of 3.2.1, with the default Twenty Eleven theme. I'm running Multiple Galleries 0.4.1, and have disabled all other plugins for troubleshooting purposes.
List of (temporarily deactivated) plugins installed:
Akismet (Never activated)
Jetpack (Never activated)
Social Media Widget (Usually activated)
WP-Slimbox2 (Usually activated)