A graphical editing system which allows a user to modify a selection gesture without having to redraw the entire gesture. The system defines a selection with an enclosure that is treated as a graphical object that can be contorted in a style consistent with the specific application. The enclosure can be altered, i.e., reshaped by a set of gestures which allow the user to expand or reduce the size of the enclosure. These alteration gestures activate specified points or portions of the enclosure to control its shape. If a selection enclosure is drawn, it can be altered to include or exclude additional data by drawing a line segment that is detected by its location relative to the selection enclosure as an alteration gesture to reshape the existing enclosure to include the line segment.