Seems to be starting from IE10? For touch screen operation to optimize the content display of the browser, IE browser provides a floating display, auto-hide scroll bar style, but this style can cause some problems in some cases, such as ...
In fact, by default, the desktop version of IE should be the traditional scroll bar style, and in the application version of IE, the scroll bar is the default is floating display, auto-hide.
But may find that some use the bootstrap style of the site, will also appear the same situation, Google a bit, found that this is because bootstrap set a CSS properties:
{ width: device-width;}
Source: http://channel9.msdn.com/Forums/Coffeehouse/IE10-how-does-the-scrollbar-autohide-on-buildwindowscom-microsoftcom
If you want to change the style of the scroll bar, you can force a style for IE browser:
{ -ms-overflow-style: scrollbar;}
msdn:https://msdn.microsoft.com/en-us/library/ie/hh771902 (v=vs.85). aspx
In Internet Explorer, use bootstrap to make the page scroll bar floating display, auto-hide, automatically disappear