A node of a collaboration system is provided to establish communication with other nodes, store data identifying graphical targets having locations in a virtual workspace and including locations in the virtual workspace of the identified graphical targets, and compute a mapping of a local client viewport to a local client screen space. The node is configured to render on the local client screen space graphical targets having locations within the local client viewport, provide a user interface to display a list of viewport markers representing viewports, where each viewport defines an area in the workspace, and respond to an input indicating a selected viewport marker from the list of viewport markers, update the local client viewport to match the location and dimensions of the viewport represented by the selected viewport marker, and render on the local client screen space graphical targets having locations within the updated local client viewport.