is that a bug?
i on drag the slider and the simulation goes unpredictable. For your info.

By the way, it might be useful if you could write down the changes you made so that we can learn what differences and enhancements were made to improve the design of the simulation :)
For example, I made some changes to the vernier caliper to have <> [img];topic=1532.0;attach=1919[/img]steps last year, and Prof Hwang realised it could be useful for students to be able to change the position of the applet step by step and he added it to his original applet Everyone learns!!! Professional Learning Community!! Yeah..

Thus, I hope you are not just changing the interface because everyone should learn from each other.  ;D :D