No warning when leaving object editor after starting editions

Reproduction steps:

• Create a new JSX object in a page and save the page
• Return to the object editor, and starts editing the JSX code
• Click on a browser bookmark to go to another page

Expected result:

• the current page is not left and a warning is displayed about data being not saved yet

Obtained result:

• the browser immediately navigates to the clicked linked. Using the back button in history doesn't allow to retrieve the unsaved data (because of lazy loading of the objects)