[wp-trac] [WordPress Trac] #8957: 100% CPU, unresponsive javascript when leaving admin "Edit Posts" and "Edit Post" pages

[WordPress Trac]

#8957: 100% CPU, unresponsive javascript when leaving admin "Edit Posts" and "Edit
Post" pages
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 Reporter:  _timk         |       Owner:  azaozz                                                           
     Type:  defect (bug)  |      Status:  new                                                              
 Priority:  normal        |   Milestone:  2.8                                                              
Component:  JavaScript    |     Version:  2.7                                                              
 Severity:  major         |    Keywords:  unresponsive script javascript cpu browser client categories slow
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 I'm experiencing javascript timeouts and high CPU usage when transitioning
 between "Edit Posts" and "Edit Post" pages in my WordPress admin
 interface.

 From the post list, when I click an edit link or a link to the next page
 of posts, Firefox shoots to 100% CPU usage for 5-8 seconds, usually shows
 the "Unresponsive Script" warning box, and then finally loads the next
 page.  The same happens transitioning from an Edit Post page back to the
 post list, or reloading the post list page.

 If I disable javascript in my browser, the problem goes away.

 I think this is related to the number of categories I'm using--I have a
 couple thousand.  The behavior makes me think something client-side is
 processing that category list on page unload, causing the delay.  I
 realize this is probably a corner case, but I think the admin UI should be
 able to scale.

 I'm a web developer.  If someone has an idea on where to look, I may be
 able to help trace the problem.  I'm just not sure where to begin.

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Ticket URL: <http://trac.wordpress.org/ticket/8957>
WordPress Trac <http://trac.wordpress.org/>
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