Editor, DFW v2: use a 2D transform to force repaint of the admin toolbar, only on `#wp-toolbar`. Fixes calculating the position of the right sidebar on fade-in and removes any performance and stacking implications. 
Props joemcgill, see #30516.
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git-svn-id: http://core.svn.wordpress.org/trunk@30700 1a063a9b-81f0-0310-95a4-ce76da25c4cd