Ahh, I finally reproduced the behavior!
I am using a custom control following this link: http://www.sitefinity.com/support/kb/sitefinity-3-x/how-to-wrap-generic-conent-in-a-user-control.aspx
that also has a property on the advanced tab for the title input.
If I first put the control on the page, I can enter content on the Basic tab, and then go to the advanced tab and enter a title. I can go back and forth between the two tabs and the content is not lost. I can even go back into the control and go back and forth between the tabs editing the content and it keeps (which is the original bug that was fixed by the link above).
The problem arises when you use Shared content. If you make any changes to it or even simply add the shared content, then switch to the Advanced tab then back to the Basic tab, it does not keep what you just did ior any changes made to the Shared Content.
One thing i noticed is that without the Shared Content, on the Advnaced Tab the box for ProviderName was blank. But when I was using Shared Content the box had "Generic_Content" .
Does this make sense? I can send screen shots if you like...