Bug 29853 [Workbench] OpenWithMenu and setFile
The constructor that only takes the IWorkbenchPage mentions that the user must use the setFile method...this method does not exist.
bundles/org.eclipse.ui.ide/extensions/org/eclipse/ui/actions/OpenWithMenu.java
*
     * @param editor the editor descriptor, or null for the system editor
     * @param openUsingDescriptor use the descriptor's editor ID for opening if false (normal case),
     * or use the descriptor itself if true (needed to fix bug 178235).
     */
    private void openEditor(IEditorDescriptor editor, boolean openUsingDescriptor) {
        IFile file = getFileResource();
        if (file == null) {
            return;
        }
        try {
        	if (openUsingDescriptor) {
        		((WorkbenchPage) page).openEditorFromDescriptor(new FileEditorInput(file), editor, true, null);
        	} else {
	            String editorId = editor == null ? IEditorRegistry.SYSTEM_EXTERNAL_EDITOR_ID
	                    : editor.getId();
	            
	            ((WorkbenchPage) page).openEditor(new FileEditorInput(file), editorId, true, MATCH_BOTH);
	            
	            IDE.setDefaultEditor(file, editorId);
        	}
        } catch (PartInitException e) {
            DialogUtil.openError(page.getWorkbenchWindow().getShell(),
                    IDEWorkbenchMessages.OpenWithMenu_dialogTitle,
                    e.getMessage(), e);
        }
    }
    /**
     * Creates the menu item for clearing the current selection.
     *