Why doesn't scrolling with the mouse wheel of a modal window in google chrome work?

Question

Google Chrome

There is an image that opens in the bootstrap modal window. When the image is large, scrolling appears, which works fine in firefox and ie10, but in chrome, scrolling with the mouse wheel does not work. However, scrolling with the arrows and the scrollbar continues to work.
If you open the developer tools while the modal window is hanging, then scrolling with the wheel starts working, but after closing the tools and opening a new modal window, it does not work again.
What could be the problem?
here is an example: vs-temp.16mb.com

Answer 1

Probably overflow-y somewhere in the css modal body...