Algodoo

I don't understand what your complaint is. When I drag the blue ball toward the red ball, it moves as it should. So, what's the problem???

BTW - No need for profanity. Many people (like me) do not appreciate it, and people will not take you seriously when you use profanity. Thanks.

Confirmed on Algodoo 2.1.0

the problem is that the distance between the two FIXED geometries decreases and i know that it isn't very important but , simply , it is a bug too

No, not a bug. It works as expected, based on my own experience with Algodoo. First off, I had to set the "strength" and "max force" of my Drag Tool to +infinite in order to move the blue and grey circles. The reason why the "Normal" circles do not come together is because they both move in the same direction that your Drag Tool pushes them. And that's because the pos variable for the smaller circle is not fixed. It is a value that will change as the circle's position changes. In the small red circle, you use executable script to set the pos position, which means that the position of the circle will stay glued to its position unless (and ONLY unless) the position (x and y) values change. So, with the small red ball stuck in its current position, the Drag Tool can push the blue ball toward it, and the distance will grow smaller and smaller until they collide.

If you do not like how it works, or you feel that it defies the laws of physics (or whatever) then you can request a change or a "fix" by submitting your request through the Algodoo forum.

okay you convinced me ,note that I do not take much time on this and you yes so I'm wrong