In my case, the reason it didn't work was because the camera's settings, not ML's, changed(on their own). Would anything else cause the Dual Iso to not function - with the info I provided? The reason I ask, is because for it to be more obvious in my case, it would require for someone(coder) to go through ML and consider, and list, every possible combination and give the solution. I don't know much about coding, but I do know a bit about manufacturing, and I know that the easier it is for the user the more complicated it becomes for the designer/mechanic, coder, etc -- it also opens the door for more bugs/conflicts to be created. The pop screen was not needed in my case, I already knew the feature was not working, I just didn't know why. I had suspected an issue with ML, not Canon's, side of the OS. I for one, don't think you can/should make things stupid proof.