Bug 12802 modify parameters: should be enabled if a parameter is selected in the editor [refactoring]
currently, you have to select a method
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/actions/ModifyParametersAction.java
}
	
	/*
	 * @see SelectionDispatchAction#selectionChanged(IStructuredSelection)
	 */
	protected void selectionChanged(IStructuredSelection selection) {
		setEnabled(canEnable(selection));
	}
    /*
     * @see SelectionDispatchAction#selectionChanged(ITextSelection)
     */
	protected void selectionChanged(ITextSelection selection) {
	}
	
	/*
	 * @see SelectionDispatchAction#run(IStructuredSelection)
	 */
	protected void run(IStructuredSelection selection) {
		startRefactoring();
	}
    /*
     * @see SelectionDispatchAction#run(ITextSelection)
     */
	protected void run(ITextSelection selection) {
		if (! canRun(selection)){
			String unavailable= RefactoringMessages.getString("ModifyParametersAction.unavailable"); 
			MessageDialog.openInformation(getShell(), RefactoringMessages.getString("OpenRefactoringWizardAction.unavailable"), unavailable); 
			fRefactoring= null;
			return;
		}