Hi.  I got thrown into a webmaster role supporting a DNN site not too long ago.  Been feeling my way around learning how it works.  Well, I have a page "Rec Centers".  Added three new pages that use that Rec Centers page as parent; Group A, Group B and Group C.  Spent awhile adding child pages to each of those three for each center's info page. 

 After that was all done, I wanted to change the title under "Group C" page.  I saw when you go to Page Settings for the page, it has Page Name and Page Title.  I figured Page Name is what will show in the navigation bar and title was the black text that was at the top of the page's content window.  Changed the title to something like "Group C Rec Center List" and hit update.  All the sudden, blammo, I lost all of Group C's children.  Now the navbar on left, instead of showing Group C children, shows my Group A/B/C.  

 Auuugh!  What happened??  Why does changing a page title cause this kind of snafu?  I thought maybe I somehow accidently changed the parent but when I check it, it is correct.  I went to Admin, Page Management and expanded the top level "Rec Centers" and I see the 3 Group A/B/C.  I see + left of Group A and B showing their children, but C has none.

 ???

Thanks for the reply. I'm using 6.1.5.142 and the menu is DDR Menu module. I actually figured it out, well, kinda. I was poking in the SQL server because I figured they -had- to still be there. I found them in the tabs table. I went and checked a page under Group A that was still visible, the only difference I found (well, aside from the parentID) was level 7 on the Group A child whilst the missing Group C child was level 2. Updated all Group C children to level 7 and voila, they appeared (after I did a cache flush).

Weird.