Empty hiero tags
Steps to reproduce:
1.Open the editor
2.Open the hiero insertion tool
3.Now without closing it open another dialog box for example:Click on Latex/Special Characters/Reference etc.
4.Close the second window
5.Save the page
The hiero insertion tool is also getting closed after step 4 but if you go to edit source you will see empty hiero tags
Now if you log out and press the back button on the browser and try editing the page as anonymous user , there are yellow bordered boxes saying "Sorry this element can only be edited in source mode now", on the positions where empty hiero tags are added
See the screenshots attached.