I'm trying to use mousePressed in the act methode of an object as following: if (Greenfoot.mousePressed(this)) { System.out.println("pressed"); } Everything works great, until I'm changing the cell size in MyWorld from 1 to 50: super(10, 10, 50); Now the mousePressed event for my object isn't firing (stays false). Important: This is working on Greenfoot 3.5.2, but I have to use 3.5.0.