File Editing

Greetings Fellow Flash guru’s! I got a little concern about editing with a publish website. To be more concise in what i’m talking about, go to the website that i’m building

then click on welcome or any other section. when i click on the text, why it’s deleting? Well i know it’s not deleting from the actual file because if you go back it’s there again. how do i fix that error? I attached the ISA Mission fla file with this message. Please help. Thanks in advance.