Parent physics help?

Hi, I need help fixing my code that used to work in previous blender. It is a simple grab(setParent) and throw(removeParent) function. A bug? or something seems to disabled it, I will try to explain in depth. Usually with “Show Physics Visualization” turned on I’d see an object with its “physic box” following it around even as I parented it and everything works fine but in 2.71 when I parented an object to myself even though the child object still follows me around, its “physic box” hang and stuck in the space where I last parented it, so when I moved away from the location(leaving behind its “physic box”) it also disabled my throw(removeParent) function, the only way I can fix it for now is to get back to where its “physic box” was and it(removeParent) works again. Is there any other solution? Thanks.

Maybe checking the compound option could solve this?