Abstract: An annotation system may include a presentation electronic device in communication with an input device and a user interface, and a computer-readable storage medium in communication with the presentation electronic device. The computer-readable storage medium may include one or more programming instructions that, when executed, cause the presentation electronic device to identify one or more open windows that are displayed via the user interface, where each open window comprises underlying content, cause a glass pane window to be displayed in front of the identified open windows, such that the underlying content of one or more of the identified open windows is visible through the glass pane window, receive input from the input device, determine whether the received input comprises an annotation, and in response to determining that the received input is an annotation, cause a visual representation of the annotation to be displayed on the glass pane window.