Open Radar

 
Summary:

When dragging a finger from offscreen onto the top edge of the iPhone's screen, the touchesBegan:withEvent, touchesMoved:withEvent:, and touchesEnded:withEvent: handlers are never called. This does not occur when dragging a finger from offscreen onto the bottom, right, or left edges of the screen. 

Steps to reproduce:

1. Open any application which uses the entire screen (let's say Calculator for this example).
2. Drag a finger from offscreen onto the bottom edge of the screen and move it over the calculator buttons. You should see the calculator buttons change to the "pressed" state as your finger moves over them.
3. Now drag a finger from a position offscreen directly over the top edge and onto the screen, and move it around in the same manner. 

Expected results:

You should see the calculator buttons change to the "pressed" state as in step 2.

Actual results:

The calculator buttons will not change state, since the app is not receiving any touch events.

Regression: 

None that I'm aware of.

Notes:

This appears to depend on the screen orientation. Tests with landscape-oriented apps (iBone for example) show the same behavior when dragging from offscreen onto the left edge (the edge that the iPhone would consider "top" given the orientation).