mouseClicked() doesn't fire when you use P2D or P3D renderer and call cursor in draw()

When you run this sketch...

``` java
void setup() {
  size(100, 100, P2D);
}

void draw() {
  cursor(ARROW);
}

void mouseClicked() {
  println("Mouse clicked!");
}
```

...and click inside the window, nothing gets printed to the console. It will print the message if you comment out either `cursor(ARROW)` or `size(100, 100, P2D)` (or just use the default renderer).
