There's no reference to this in "Tog on Interface" either, but he repeatedly references Fitt's law. I think that applies to the "escape angle" as well.
I think it follows from Fitts' Law or rather is its reverse:
If the cursor is outside an area, the bigger and closer this area is the easier it is to purposefully hit.
⇔
If the cursor is inside an area, the bigger this area is and the farther away its borders are, the harder it is to accidentally leave.
Comments
There's no reference to this in "Tog on Interface" either, but he repeatedly references Fitt's law. I think that applies to the "escape angle" as well.
I think it follows from Fitts' Law or rather is its reverse:
If the cursor is outside an area, the bigger and closer this area is the easier it is to purposefully hit. ⇔ If the cursor is inside an area, the bigger this area is and the farther away its borders are, the harder it is to accidentally leave.