Character of operating system of pocket PC is true very look like with the character of PC using operating system windows. Pocket PC recognize the existence of file association owning certain extension with the program to use to run the file.
Pocket PC also recognize the same thing. Generally these associations made by the program while the installation. It is possible, you install program that owning a same function, hence last installation program take over the association with the certain file. This matter can bother, especially if last installation program really own a disappointed quality.
One of an easiest alternative by using Resco File Explorer program. You can alter the association of file easily. Click and hold up the stylus at file to be altered by its association, then select the “Associate With” and determine the program to be used to alter the file.

Usefull reference:

Popularity: 45% [?]