To ensure other users do not override your work within the CMS we do have a strict lock and logout process. If another user has stated you are editing the Stack however you have exited the browser widow, you will need to "Force Unlock" the CMS as per the below steps:
Click into the "CMS"
If the CMS is locked, you will have to click " Force Unlock" to give other users access
In the right corner, you will see the drop down to "logout"
To avoid this in future follow the below steps to log out:
When in the CMS, click " Home"
One you are back on the My Properties page, in the right corner, you will see the drop down to "logout"