I'm running InfoPath 2010 on Windows 7. I recently installed IE10 and this appears to have forced a semi-Windows-8-type theme onto the InfoPath Filler forms. In principle I don't like this (apps like that should use the current OS theme), but more importantly some of the controls are now visually broken.
For Combo boxes (the ones you can type or select in; ordinary dropdowns are actually OK), the button to drop them down doesn't line up properly. With checkboxes, you can no longer tell the difference between enabled and disabled. Furthermore, the checkbox click behaviour is that of an enabled checkbox: it highlights when you hover and darkens when you click but then just does not actually place a check in the box. This is confusing to users when a form design heavily utilises the enabled/disabled appearance.
I built a basic HTML form to see if I could repeat this in IE itself, but it seems to be an InfoPath Filler specific problem triggered by the IE changes. Also the problem only seems to show with the Aero theme in Windows 7 - if I drop back to Classic, the controls are appropriately coloured.
I have attached a screenshot of a portion of an InfoPath 2010 Filler form showing this problem