WordPress Admin had an issue on editing and saving posts (see the WP Forums).
I assume that this issue might be related to the Admin Drop Down Menu plug-in,
since this has been reported by other WP users as well.
This is the call this causes FireBug to switch into debug mode (JS execution paused):
Ordinary utils.js should get queued up around line 31 by this call – but it doesn’t:
A quick workaround is to open /wp-admin/admin-header.php and
adding the following line just before that function call (around line 52):
In newer versions of WordPress this issue doesn’t exist anymore…