thanks!

just for ur info
i copied into the on drag action of the blue object the codes from objectnewdesignFKH, the same thing the blue object pops down when the jaws are meeting the blue object.

so what i did was i disabled objectnewdesignFKH

and enabled back the working codes from objectnewdesign....and the bug is gone!

i think the codes u made in  objectnewdesignFKH need to be inside the blue object while the codes

.....................
else if((ox>x2+x-w/2)&&(oy>oymin-h/2)&&(oy<=oymax-h/2)){ // right jaw hit object and inside jaws

  ox=x2+x-w/2; // to force the blue object into the open jaws
}

solved the bug.

the new applet will be hosted there http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=684.msg2452#msg2452

thanks for taking the your applet to the next level for usability in improving learning ;D.