I've associated .xul with Notepad++ so if I double-click on a .xul file, it will open in Notepad++. But Notepad++ doesn't know that XUL is just a particular type of XML, so I then have to manually click on "Language > XML" to get XML syntax highlighting. Is there a way that I can tell it: "every time you open a file with the extension .xul, automatically switch to the XML language"?


All you have to do is tell Notepad++ that "xul" files are actually "XML" files.

  1. Go to Settings > Style Configurator
  2. Under Language, scroll down and highlight "XML"
  3. At the bottom, under User ext. type in "xul"
  4. Press Save & Close
  5. Open your file and it should now highlight properly.

Some other helpful links:

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    And if you want to add more than one (for example, I'm also adding 'rdf' -- yup, I'm doing Firefox extension development) then just separate them with spaces. – MatrixFrog Jun 11 '10 at 22:21
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    I'm saving it and it works for the session but it doesn't persist. When I restart Notepad++, it's not there anymore. – strider Mar 27 '14 at 15:31
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    Run it as Administrator and it persists. – strider Mar 27 '14 at 15:37
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    Note that for user-defined languages, the same can be done from the language configuration window in Language > Define your language... > user language : <your language> in the Ext. field. – yco Apr 20 '16 at 9:54
  • Awsome! +1 for you! – Ivijan Stefan Stipić Nov 11 '16 at 17:55

Here is the instructions for user defined languages. With pictures.

Select: Language --> Define Your Language:

Select: Language --> Define Your Language

Make sure you omit "." from extension in the Ext. box, or it wont work:

Make sure you omit "." from extension in the Ext. box, or it wont work.

  • 1
    Please read the question again carefully. Your answer does not answer the original question. This is an answer to some other question. – DavidPostill Jan 29 '17 at 15:35

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