Draggable with scrollbar inside the element follows the mouse pointer if clicked on the scrollbar.

I created a "draggable" pop-up window of a fixed size and with css setting overflow-y:auto for the contents of that draggable item, that way the pop-up doesn't overgrow the height of the screen, and also could be moved around the screen. When I click on the scrollbar, the pop-up starts to follow the mouse pointer and there is no way to stop it. It happens almost in every browser.

jQuery version: 1.7.2