Edit Mode can be enabled and disabled from the Edit menu. A tick will appear next to the Edit Mode menu item when enabled.
When Edit Mode is enabled, the figure joints can be repositioned by dragging the handle without effecting the position of any other joint. The length of the segments connected to the moved joint will therefore change.
When Edit Mode is disabled, the figure can be moved as a normal figure - this includes the use of the Ctrl key to change the length of a single segment and the Alt key to scale or rotate the entire figure.