Examine the door to see where you can reinforce it without interfering with the cam or making the door thicker. Glue the plastic tab back in place, using a piece of flat toothpick or scrap of plastic to reinforce it. Use super glue or epoxy. Do not use heat to set the epoxy - this plastic softens very easily.

In the picture, you can see the broken tab, and the bit of toothpick next to it.