The forward part of the canopy was designed to be stiffened. Depending on the vintage of your airplane, this was done by glass/ foam inside the forward canopy frame, or by an aluminum sheet riveted inside the same area. Either one will provide much greater rigidity to the frame. Did you build the airplane or buy it? If you bought it, you might not know the answer, but if you can take a picture of the inside of the forward canopy while it's open, that might help us diagnose.
Also, when opening the canopy from the rear, it helps to push inwards on the lower rear corner of the canopy. Sort of keeps the thing in alignment.