In Windows OS. When I would like to open file without default program, I right click on file and choose "Open with". In my pc for .xml file there is big list of editor. I would like to get rid of that list. Even few of listed programs does not exist on my system.
What version of Windows are you running?
If you are using Windows XP or Vista, you can use this small application to edit your Open With Menu...
I figure it should also work with Windows 7 but I haven't tried it myself.
On Windows XP you can edit the list using Registry Editor. It is best to do this only if you are familiar with editing the registry, and you should consider backing up the registry before you begin.
I would go with the software as it covers more systems.