Apologies in advance for the wordy-ness. If any one would prefer, I have a small project I mocked up to isolate this very weird behavior.

To observe:
1) Create a simple windows form project
2) Add a TabControl to your form
3) Enable autoscroll on TabPage1
4) Create a custom user control with a height greater than TabPage1
5) To your user control add an InkPicture control. (Put it on the bottom and make it big enough to situate as described in step 6.)
6) Add the user control to TabPage1 of your form. Place it in such a way so that when the form is loaded with the vertical scroll bar at its uppermost position, the InkPicture control will be visible at the bottom of the TabPage but will also extend out into the 'out of form' scrollable area.
7) Click on the InkPicture.

If your application behaves as mine, the scrollbar will move down. Am I wrong to think that this is unexpected behavior? Anyone know how I can make it stop behaving this way? If anyone mocks this up and it doesn't behave this way, PLEASE let me know.

Some other info to chew on...
As far as I can tell the Scroll event does not fire anywhere when this happens. (I added handlers w/ breakpoints to all controls w/ Scroll events. No hits. I also added an override for the WndProc method and checked messages for WM_VSCROLL (my mockup only had the vertical scroll). No scroll messages.)

Any helpful information would be much appreciated.

Thanks in advance.