Wiki editor - User can lose changes more easily now

Unlike the WYSIWYG editor, the Wiki editor doesn't warn users when they leave the editor without saving their changes. From users' perspective, there is no reason for different handling though.

Please note that this was also the case in older XWiki versions. But now that it is much easier to unintentionally click on the "Edit" button instead of selecting another editor type (there is no practical on-hover popup anymore, just one narrow arrow instead), this makes this shortcoming even more disturbing.