Users can set a minimum width or height for a window in order to prevent a window from becoming too small. This constraint on the window width or height can be removed by a corresponding release operation. Both the set and release minimum width and height operations are performed by selecting the appropriate operation from the window menu. Users can set minimum width and height constraints on windows at any level in the hierarchy. However, minimum values are propagated up in the hierarchy, thus possibly updating the constraints of higher level windows. When constraints are unsatisfiable, operation is blocked.