1. A computer program product for visual connectivity of objects using event propagation, the computer-program product comprising: a computer readable storage device containing computer executable program code stored thereon, the computer executable program code comprising: computer executable program code to: output, for display, a first object and a second object of a plurality of objects, the first object being a publisher of events and the second object being a subscriber of events from the first object, wherein at least the first object is also a subscriber of events from a third object in the plurality of objects or the second object is also a publisher of events to the third object in the plurality of objects; computer executable program code to: responsive to receiving user input to move the first object towards the second object, output, for display, a visual connection cue for at least one of the first object or the second object, the visual connection cue representing a communication capability of the at least one of the first object or the second object to communicate the events with another of the first object and the second object; computer executable program code to: while the first object moves towards the second object, adjust an appearance of the visual connection cue, wherein the appearance of the visual connection cue is indicative of the at least one of the first object or the second object being at least one of a subscriber of events or a publisher of events; computer executable program code to: identify an event propagation precedence that indicates whether event propagation of the events from the first object as the publisher to the second object as the subscriber is permitted; and computer executable program code to: connect the first object with the second object, based on the event propagation precedence, to communicate the events from the first object to the second object.