[RESOLVED] Question about using GetWindowRect

Don't understand something.

1) If my Form is at screen location 0,0 to 22,22 GetWindowRect returns 1

2) If my Form is at screen location 23,23 to 37,37 GetWindowRect returns 2

3) If my Form is at screen location 38,38 to 52,52 GetWindowRect returns 3

4) If my Form is at screen location 53,53 to 67,67 GetWindowRect returns 4

etc, etc

Now I see that the range is 15 for examples 2, 3, and 4 but it is 23 for example 1

Can someone explain this?