It's because you're using tabs. I have a jQuery tabset floating around here somewhere.. let me look around and I'll post it.

Removing the tabs did indeed solve the issue.
Thanks a lot, it was doing my head in.
A working variant of TabSet and Tab would be much appreciated!

http://carlinowebdesign.com/tabs.zip

Place in a folder named "tabs", and run a flush.

Example code:

return new FieldSet(
	new HorizontalTabSet("Root",
		new Tab('Info',
    		new TextField('Name')
    	),
    	new VerticalTabSet('Schools',
    		new Tab('DOM',
	    		new DataObjectManager(
	    			$this,
	    			'Schools',
	    			'School',
	    			array('Name' => 'Name', 'Year' => 'Year', 'Degree' => 'Degree')
	    		)
	    	),
	    	new Tab('Bio',
	    		new TextareaField('Bio')
	    	)	
    	),
    	new Tab('RandomThings',
    			new CheckboxSetField('RandomThings','Random things',DataObject::get("RandomThing")->toDropdownMap('ID','Foo'))
    	)
    )
);

Notice that for nested tabsets, you can use VerticalTabSet to hide and show fields on click from within a horizontal tab.

Haven't tested in 2.4, and just made a fix that should help. Let me know how that works for you.

Thanks UC, those tabs do play nice with DOM.
Why don't you bundle them with your DOM release(s)?
Doubt I'm the only person using tabs in combination with DOM.

Cause I assumed they didn't work! Glad to hear it's working for you. I think I will roll that in and let people play around with it.

The HorizontalTabSet is great, solve my "$ is not a function" too. The new look & feel for the tabs blends well with the popup!

i stumbled upon this and i must say that this is really really great.

So I just wanted to inform you, that these tabs interfiere with Uploadify - so you have to use FileIFrameField.

It's a conflict with jQuery and I solved it this way...
- Modified the file imagegallerymanager_popup.js in folder image_galery/javascript this way:

$.noConflict();

jQuery(function() {
jQuery('.rotate-controls a').click(function() {
link = $(this).attr('href');
jQuery.ajax({
url: link,
success: function(html){
jQuery('#preview-image img.preview').attr('src', html);
}

});
return false;
});
});

jQuery().ajaxSend(function(r,s){
jQuery(".ajax-loader").slideDown();
});

jQuery().ajaxStop(function(r,s){
jQuery(".ajax-loader").slideUp();
});

After this modification, '$ is not a function' error gone, and uploads begin to function as usual....