Customizing the behavior of the snap feature for my application

Question

Hi, I'm willing to change default aero-snap behavior for my application. The point is that my main window should always have the defined proportions.

The troubles that I now have:

1. The preview rectangle which shows how the window will be placed after snapping is displayed incorrect.

I've figured out, that when my WM_GETMINMAXINFO handler is quite simple the ptMaxTrackSize is used to display this preview rectangle and it is displayed fine. However, as soon as I add any logic in the WM_GETMINMAXINFO handler the system displays this preview rectangle of the default size and seems not to be using ptMaxTrackSize.

2. When I'm trying to resize my window and move the cursor to the top of the screen or down to the taskbar and then release the mouse button the window snaps the top of the desktop and taskbar by just increasing the height of the window only. It seems that the system doesn't try to stretch the window accordingly to the ptMaxTrackSize. It's quite different behavior from one that I'm seeing while window snaps the borders. And I don't see any good way to keep the proportions of my window while snapping that way.