Tip: Although you can open resource files with other editors
you are advised to only use the workbench Message
Set editor to work with message set files because this editor correctly validates
changes made to the messageSet.mset files when
they are saved. Other editors might not do this.
To open a message set so that you can view or edit its contents:
Switch to the Broker Application Development
perspective.
In the Resource Navigator, right-click the messageSet.mset file
of the message set that you are opening then click Open on
the pop-up menu. This launches the Message Set editor for
the selected file.