edit: maybe this should go under site bugs, instead of feature requests... mod please move if more appropraite.
This is only an issue for me when using my iPad to reply to posts on dslr, so it should be an iPad specific fix, but this might also apply to iPhone and other small screen devices.
When typing into the quick reply box, and inevitably when I need to move the cursor around to fix a typo, trying to position the cursor through the magnifying glass tends to result in the box scrolling up or down, making it very difficult to place the cursor.
I think its because when you get near the top or bottom of the box it tries to be smart and scroll up or down to reveal more text for you. But as the box is so small, this happens immediately because you're already near the top or bottom, theres no point at which it will just rest. Its like trying to swat a fly with the tip of your finger.
Its kind of counter-intuitive to make something bigger on a smaller screen device, but it would make a great difference to mobile usability of the site!