Here's another usability glitch when double-tapping to select a word on the iPhone.

Suppose you're in a notes app and you're looking at a note with the keyboard deactivated. Double-tap a word near the bottom of the screen. The word is selected, as it should be. In some apps, the keyboard slides up to allow you to start editing.

The problem is that the second of your two taps lands on a point that lies within the keyboard area, so you unintentionally type whatever character corresponds to the key at that point.

This happens in Notespark and Simplenote, because they bring up the keyboard, but not in Apple's Notes app. In Notes, single-tapping brings up the keyboard but double-tapping does not, perhaps because of this very problem.

I'm not sure whether this should be considered an app problem or an OS problem. I lean toward OS, because from the user's perspective touch events should be captured by the view I actually touched. I suspect the issue is related to the way Core Animation works. The first tap immediately adds the keyboard into the view hierarchy, so technically the second tap really is in the keyboard, but you don't see the keyboard until it animates into place.

On the other hand, I would think the app should be able to deal with this fact, though I haven't thought the logic through. Maybe Apple's approach in their own app should be a hint that there's no good solution.

I wanted to include screen shots, but again, I don't have time.