Correction: When you say 'assigned the Adobe RGB 1998 profile', do you mean the AssignICCProfile tool, or the ICCProfileTransformation tool?
If you have just assigned the profile, then the change in visual appearance is normal behavior. If you have transformed pixel values, then there should be no perceptible visual change with a wide gamut profile such as Adobe RGB, as long as your monitor profile is well characterized.
At any rate, the key factor here is the ICC profile that you have assigned to your monitor in both applications. If it is different, then there is no way both applications can provide the same screen renditions. If they are the same but the profile does not characterize your monitor correctly, then there is no way to achieve consistent color reproduction.