Edit - Divide
Selecting Edit - Divide allows you to split existing polygon(s) to create two new polygons from the original. The divider may be drawn at any angle, or restricted to the ortho angles. Selecting ortho or holding shift while dragging to draw the divider locks the angles to angles set in Snap /Ortho. Pre-selecting polygons limits the polygons which are divided. The position of the metal remains the same but is now made up of two polygons.
When you select this command, the cursor changes to indicate that you may draw a dividing line. Drag the mouse where you wish to divide the polygon(s); only polygons which are intersected by the divider are affected. When you release the mouse button, the divide is executed. You may divide more than one polygon at a time. If no polygons are pre-selected, then polygons are split along the divider wherever it touches the metalization. Otherwise, only the pre-selected polygons are affected.
Holding down the shift key while selecting the Divide Polygons command, or selecting the Pin mode button 
when in the mode, allows you to draw multiple dividing lines without having to re-select the command.
