Cant change default file association

Hi,

I have installed two programs that both handle a particular file type, and both have associated themselves with the file type.

However, the wrong one has set itself as default, and I cannot fix it. When I set it to the one I want, it still stays as an option, but not as default. So when I click open as I see:

Program 1 (default) ()
_____________________________
Program 2 (1)

I want to leave Program 1 installed, but I want program 2 to be the default. Setting Program 2 as the default has no impact, however I try to change it. Any advice?

Thanks