There are probably lots of inefficiencies. This patch addresses two.
- Whenever a checkbox in "All Categories" is checked/unchecked, it syncs that new checked state with it's partner in "Most Used" and vice versa.
- On load (and maybe unload in some browsers during some kind of cleanup), wp-lists looks at each category checkbox and makes huge arrays. This is so that the current checked state of all category checkboxes is known (needed for ajax addition of categories).
The attached fixes:
- By only syncing the categories that are in both lists. To do this, various wp-admin/include/template functions have been tweaked so that they can be aware of what categories are popular.
- By vastly reducing the number of inputs wp-lists looks at on load and making slight efficiency tweaks to wp-lists.
