Notes

Since CC 2017: Code hints are not available for the custom file extensions added in MMDocumentTypes.xml

Expected: As in previous versions, user should be able to add/enable hints for the new file extensions or document types added by users

Platform: Mac and Win

Steps:
1. Launch DW & quit the app once
2. Open Extensions.txt from below path in a 3rd party text editor
Win: %appdata%AdobeDreamweaver CC 2017en_USConfiguration
Mac: ~/Library/Application Support/Adobe/Dreamweaver CC 2017/en_US/Configuration/
3. Add SS, DD and XYZ extensions to the file for a new HTML, CSS and HTML types respectively:
Add SS,DD,XYZ just before ":All Documents" on line 1
Add ,SS,XYZ just before ":HTML Documents" one line 2
Add ,DD just before ":Style Sheets" on line 8
4. Save and close the file
5. Open MMDocumentTypes.xml from below path in a 3rd party text editor
Win: %appdata%AdobeDreamweaver CC 2017en_USConfigurationDocumentTypes
Mac: ~/Library/Application Support/Adobe/Dreamweaver CC 2017/en_US/Configuration/DocumentTypes/
6. Add a new extension "ss" on line 3 for attributes: winfileextension and macfileextension --> This is to add a new extension for HTML document type
7. Add a new extension "dd" on line 12 for attributes: winfileextension and macfileextension --> This is to add a new extension for CSS document type
8. Append the below code just before </documenttypes> in the end of the file to add a new document type and save the file
<documenttype id="XYZ" internaltype="HTML" winfileextension="xyz" macfileextension="xyz" file="Default.xyz" writebyteordermark="false" mimetype="text/html">
<TITLE>
XYZ
</TITLE>
<description>
XYZ file type
</description>
<dtdcontext>html</dtdcontext>
</documenttype>
9. Open CodeHints.xml from below path in a 3rd party text editor.
Win: <InstalledFolder>ConfigurationCodeHints
Mac: <InstalledFolder>/Configuration/CodeHints/
10. Add below line inside <menugroup MMString:name="codehints_6" id="CodeHints_Function_Arguments"> on line 27 and save the file
<function pattern="someFunction(number)" doctypes="XYZ" source="SomeSource" icon="shared/mm/images/hintFunction.png"/>
11. Launch DW and open the attached files
12. Open Tag Library from Tools menu
13. Select HTML Tags in the first list box and enable XYZ in the 2nd list box
14. Click on Ok button and close the window
15. Type someFunction in the .xyz file
Result: No hint is displayed
Expected: someFunction(number) hint added in step 12 is displayed
16. Type < inside .xyz and .ss file
Result: No hint is displayed
Expected: HTML hints are displayed
16. Type hei inside .dd file inside a rule
Result: No hint is displayed
Expected: CSS hints are displayed
18. Type < in .xyz file
Result: No hints are displayed
Expected: CSS hints are displayed

Workaround: Select the required file type in file mode dropdown in document statusbar.
This might not work for all file types.