The lxde desktop is a lightweight desktop for linux systems. Similar to xfce but requires lesser resources than the heavier gnome and kde desktops. Many linux distros have a lxde spin as well for those who prefer the lxde desktops. For example Lubuntu is the lxde variant of ubuntu. Fedora too has a lxde version.
I recently installed Lubuntu 12.10 on my old netbook. Everything was very fine, except that I noticed that mouse clicks were not responsive. Double clicks over desktop icons did not work at first shot and had to be done again and again. Setting the mouse sensitivity from the settings did not help either.
The solution was to do some configuration change which is as follows :
1. Create a file name .gtkrc-2.0 in the home directory. If the file does not exist then create it.
2. Add the following line to the file
Save the file. Logout and login to test double click speed on desktop icons.