Zend certified PHP/Magento developer

Configure Bluefish to Open .ui Files as XML

I am new to the Bluefish (v 2.2.12) editor and I am trying to out to edit .ui files. These files are XML, but they open in the editor as plain text. If I change the extension to .xml they are recognized as XML and I can edit them as I wish. How can I update the configuration such that additional file extensions can be opened as XML? I’ve found 10 year old instructions, but they seem so out of date they are not relevant to this release.