Start Word 2010.
Create an new Document.
Type some text and save.
Create 2 contiguous RichEdit Content Controls seperated by exactly one new line character.
Name them ControlA and Control B.Type some text in them.
Now create control C To contain Controls A and B.
Now Create  bookmark from start of Control A to one past the end of Control A but not including the new line character seperating it from Control B.
Save the document. Close it and reopen it.
the Bookmark has been deleted.

You may contact me at sameersingbal@yahoo.com and I will send you the file  which makes it even more easy to reproduce the bug.

• Moved by Fei XueMicrosoft contingent staff 5 hours 34 minutes ago

Hi SameerSignbal,

Thanks for posting in MSDN forum.

Since the issue is more relative to end-user, I would like to move it to Word IT Pro Dicussions forum.

The reason why we recommend posting appropriately is you will get the most qualified pool of respondents, and other partners who read the forums regularly can either share their knowledge or learn from your interaction with us.

Thanks for your understanding.

Regards & Fei