Dragging scroll bar thumb on Win7 Chrome causes page to jump

[sidkoul]

When a user uses their mouse to drag the scroll bar's thumb (i.e. the grip or elevator) down a page with a large number of thumbnails, the thumb will be forced to the top of the page after a batch of images have been lazy loaded.

This is constrained to:

• Windows 7 (OS X not affected)
• Chrome (latest build, version 34.x)
• a Third Level ID page with a large number of thumbnails
• e.g. Simple Key > Woody plants > Broad-leaved woody plants
• directly manipulating the thumb of the scroll bar

Using the mouse's scroll wheel, the scroll bar's up and down button controls, or the keyboard all work correctly. It's only when the user drags the thumb, and a new batch of images have been loaded that this behavior is triggered.