title: How to add an arbitrary ProblemMarker in Eclipse RCP?
body: <p>Without relying on any external validation, I want to simply invoke an IAction (say from a right click menu option on a file) and create a ProblemMarker. I would just have my own validation logic, inside the IAction, which validates the file input and adds this ProblemMarker at a given location with a given custom message. It would also be able to delete all markers too. I assume if you can add a marker that you can also delete one too.</p>