You are editing a text for a long period of time without saving it. Then you click Save. Your changes disappear and you see the original text.
The problem is, that if you don't save for a long time your session times out. If you used Active Directory authentication, you are automatically logged in again. But because of the new session the text is loaded from the database and your postback information gets lost.
If you do not use Active Directory authentication, you get a login-page in the popup, if you log in entering your username and password, you loose the text in the same way.
There is no real solution yet, but as workaround:
Do not let your session to timeout. Periodically save the changes you've made. Per default your session will timeout in 60 minutes, but this value can be configured in the web.config. Consult your CMS-Administrator, if you are not sure about the timeout. If you switch back to AxCMS.net-windows after a long inactivity period, copy the text into clipboard before you save it. So you can restore it if you get a timeout.
AxCMS.net versions: All versions