1. A method comprising: in response to detecting a first user-interface gesture that indicates entry into a first graphical element in a group of graphical elements triggering a first event, propagating, using a processor of a computer, the first event to the group of graphical elements to change a behavior of the group of graphical elements to a behavior specific to the first graphical element, wherein the group of graphical elements forms a non-rectangular region; detecting a second user-interface gesture that indicates exit from the first graphical element triggering a second event; in response to determining that a closest border of the first graphical element is shared with a another graphical element in the group of graphical elements, delaying processing of the second event by a specific amount of time to allow movement over a gap between the first graphical element and the another graphical element, wherein the group of graphical elements retains the behavior while there is movement over the gap; and stopping propagation of the second event to the group of graphical elements, wherein the group of graphical elements retains the behavior; and in response to determining that the closest border of the first graphical element is not shared with another graphical element in the group of graphical elements, propagating the second event to the group of graphical elements to change the behavior of the group of graphical elements.