This is fine so long as the element you want to resize is on the edge. What is needed is a way to control the resizing of all elements in a group. For each element make left or right anchored or moveable (relative to the group) as well as top or bottom (but not both!). Then made width and height either fixed, resizing or scaling. There are plenty of UI tools that do just that, OmniiGraffle just needs this in v5!