Internet Explorer Filter Css doesn't work on Hide()/ Show()

[tomgrohl]

If you set a Background Gradient for IE in css (I've done it externally), like:

filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#6699CC', endColorstr='#003366');

If you use $(el).hide() or $(el).show() it sets the filter css inline but not with a value.

So it becomes:

filter: ;

And cancels the original css

[dmethvin]

Dup of #6841.