A system for displaying a combined image data from several sources on a head-mounted see-through display (HMSTD) defining a line of sight (LOS) is provided herein. The system includes: a tracker configured to track the LOS of the HMSTD; a display controller configured to display a first display area including a synthetic image data conformal to a scene viewed via the HMSTD; a trigger mechanism configured to select a desired point within the scene which intersects the LOS of the HMSTD at a time of a triggering event, wherein the display controller is configured to receive the desired point and to display a second display area on the HMSTD, wherein the second display area is positioned relative to the desired point, and wherein said display controller is further configured to modify the synthetic image data in a portion of the first display area covered by the second display area.