Bug 46164 [Tasks] Go To enabled for non-file markers
build I20031105 Go To in the Tasks view is enabled even for a manually created task. It should only be enabled for tasks on files.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/markers/internal/ActionOpenMarker.java
* Report an error message
	 * 
	 * @param message
	 */
	private void reportError(String message) {
		IStatus status = new Status(IStatus.ERROR,
				IDEWorkbenchPlugin.IDE_WORKBENCH, message);
		reportStatus(status);
	}
	/**
	 * Report the status
	 * 
	 * @param status
	 */
	private void reportStatus(IStatus status) {
		StatusAdapter adapter = new StatusAdapter(status);
		adapter.setProperty(StatusAdapter.TITLE_PROPERTY,
				MarkerMessages.OpenMarker_errorTitle);
		StatusManager.getManager().handle(adapter, StatusManager.SHOW);
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ui.actions.SelectionProviderAction#selectionChanged(org.eclipse.jface.viewers.IStructuredSelection)
	 */
	public void selectionChanged(IStructuredSelection selection) {
		setEnabled(Util.allConcreteSelection(selection));
	}
}