Choose Tools | File Formats 
(Beyond Compare | File Formats on macOS) to see and manage the entire list of file formats.
The order of the list is important. When Beyond Compare looks for a file format to use on a file, it scans this list from top to bottom, stopping on the first enabled item whose mask matches the filename. To change the order of the list, select an item and click the Move Up 
or Move Down 
button. To enable or turn off an item, select or clear its checkbox.
An item is colored red if any filename it could match is already matched by an item higher in the list. A deselected item is colored gray. An item with an empty mask cannot match any filename. To use any of these file formats, you must manually choose them in file sessions.
Note A specific session can independently enable or turn off file formats. (See Folder Compare Miscellaneous Settings.) This way you can have a special file format that is used only by one session.
See also
