Testcases:
http://www.wyavtv.org/iebug/iebugtestcase.html
a div with an applied filter becomes misplaced if a element directly above
it has a positon: relative and float:left and has a height taller than the
normal line-height and reaches down and touches the box. (see the 1st, 3rd
and 5th testcase)
In a normal div without a filter css style rule, the text is moved away only.
The following bug can be fixed by shifting the element above it up by a few
pixels or changing doctype to transitional (because transitional doctype
means there is no baseline under images, therefore the element above it does
not reach down the normal line-height and therefore IE8 does not shift it.)
However deselecting the css rule in Developer Tools (Microsoft) does not
remove the shifting. It must be not present in code for the bug to not show
up (see the even number tests in the testcase file.)
This never happens in Firefox Safari or Opera.
If you do not see what I mean, go to
http://www.wyavtv.org/iebug/screenshot.png