Syntax Highlights Not Available in Eclipse Plugin

Problem

I associated the .ext extension with Oxygen XML Author Eclipse plugin in Eclipse but an .ext file opened with the Oxygen XML Author Eclipse plugin plugin does not have syntax highlights.

Solution

Associate an extension with Oxygen XML Author Eclipse plugin in Eclipse versions 4.5-4.35 by following these steps:

Associate the .ext extension with the Oxygen XML Author Eclipse plugin plugin:
1. Open the Preferences dialog box and go to General > Editors > File Associations.
2. Add *.ext to the list of file types.
3. Select *.ext in the list by clicking it.
4. Add Oxygen XML Author Eclipse plugin to the list of Associated editors and make it the default editor.
Associate the .ext extension with the Oxygen XML content type:
1. Open the Preferences dialog box and go to General > Content Types.
2. Add *.ext to the File associations list for the Text > XML > Oxygen XML Author Eclipse plugin content type.
Click the OK button in the Eclipse preferences dialog box.

Result: Now when an *.ext file is opened, the icon and the syntax highlights should be the same as for XML files opened with the Oxygen XML Author Eclipse plugin plugin.