Whisker Menu is an alternative to the Xfce application menu that tries to make finding and launching applications easier.
The tool allows you to quickly search for the application you want to launch or, if you don't know the application name, you can browse all the applications installed on the system by browsing through categories.
To make it easier to access your favorite applications, the menu comes with a "Favorites" category - to add new items, browse the categories (or use the integrated search), right click your favorite application and select "Add to Favorites". In the same way you can also remove applications from Favorites, add them to the panel or desktop. For quick access, Whisker Menu also keeps a list of the last ten launched applications, under "Recently used".
Other features include: customizable menu icon, resizable menu window and an option to show or hide the application description.
The latest stable Whisker Menu can't be launched using a keyboard shortcut, but this feature will be added in the next release (it's already available in Git).
Install Whisker Menu in Xubuntu
Ubuntu 12.04: if you've upgraded to Xfce 4.10, the Whisker Menu PPA packages won't work for you so to use it you must compile it from source.
To install Whisker Menu in (X)Ubuntu, use the following commands:
sudo add-apt-repository ppa:gottcode/gcppa
sudo apt-get update
sudo apt-get install xfce4-whiskermenu-plugin
If you use Fedora 17 or 18, Debian 7, or openSUSE, you'll find Whisker Menu packages (available to download or use via repository) HERE.
Once installed, right click the panel and select Panel > Add New Items, then select "Whisker Menu" and click "Add".
To grab the latest code or report bugs, see Whisker Menu's GitHub page.
via Marco's Box & Lffl