A Keeper Rated 4 out of 5 stars

Pale Moon (Firefox) 9.01 - Using this with All in one Sidebar without any problem, added a button to the aios by customizing toolbar for quick access. (Could use Ctrl + Shift + k but I'm a 'mouse' user).

I have a lot of search engines installed, so the categorize feature is a welcome addition - especially as there seems to be an inordinately large space between each of the listed search engines (which may be due to a very large favicon for a couple of the search sites).

I also have to remember to reset the category to 'All' before I exit the Search Sidebar, as if I don't, I will only have access to the search engines in the category I was in in the url (omnibar) search bar. Consequently I would like to see it automatically revert to 'All'' on close, or at least have an option for it.

It would also be nice, not essential, to have the option to select/unselect all search engines in a category.

This suggestion from a review 3 years ago sounds good to me.
'Just one thing I wish you could reconsider. Categories are a bit limited. Choose a category and you lose the ability to see other search modules. Why not use a tree structure like the left pane of Windows Explorer instead? Create custom folders then drag and drop modules. Expand or collapse and choose as you wish. Seems more flexible, no?'

Overall I would recommend Search Sidebar