Switch to the Integration Development perspective.
In the Application
Development view, right-click the message
category file (*.category file extension) that
you want to delete, then click Delete. Alternatively
select the message category file in the Application
Development view, then
either click Edit > Delete, or press the Delete key.
On the Confirm Resource Delete window,
click Yes to delete the message category file.
Alternatively, to cancel the message category file deletion, either
click No or press the Esc key.
Tip: After you have deleted
a message category file, the action cannot be undone.