When you enable the Use Capture Frame option on the Observe/Control Host tab in the Preferences dialog box, the Capture Frame will open on your desktop when a remote computer establishes a Control or Observe connection to your computer.
The Capture Frame restricts the remote user’s view of your desktop. During the screen-sharing session, only the portion of your desktop that appears in the Capture Frame is displayed in the screen-sharing window on the remote computer. In addition, the screen-sharing session will not begin until you click the Play button in the upper-left corner of the Capture Frame.
Note: Do not enable the Use Capture Frame option if anyone will need to use the Control or Observe service to access your computer when you are not present. Because you must click the Play button to allow the screen-sharing session to proceed, you must be physically present at the host computer.
For additional information about using the Capture Frame, see Using the Capture Frame.