TextButtons mis-align/position when in ButtonGroups and other containers due to IE8 not supporting display: inline-block correctly. It pushes the button down out of inline position about 5-10px.

FIX NEEDED: For IE8 change the default style to for TextButton to be display: inline.

WORKAROUND: Set a style on the element to override the GXT stylesheet, e.g.

Code:
if (GXT.isIE8())
{
    button.getElement().getStyle().setDisplay(Display.INLINE);
}