Last time, we saw that Windows 7 lets you position windows to fill the left or right half of the screen by just dragging the window to the appropriate edge. (This also works for the top and bottom half of the screen.) But what if you just want a window near the edge without the automatic positioning?
Just grab the window from the far edge.
The auto-positioning behavior is triggered by the mouse position, not the window position. (This is hinted at in the animation that accompanies the docking: The ripple effect is centered on the mouse, not the window. Here are more details on Aero Snap design.) If you don't want auto-positioning to kick in, just keep the mouse away from the edge of the screen. For example, suppose you want to place a window against the left edge of the screen, but you don't want the automatic positioning to kick in. Just grab the caption bar by the area near the minimize/maximize/close buttons, then drag the window to the left edge of the screen. Since you grabbed it from the right-hand part of the caption, you can position the window freely without the mouse getting anywhere near the edge of the screen.
Similarly, if you want to position a window near the right edge, grab it near the left hand part of the caption bar (near the caption icon).
If this feature offends you so much that you would rather have it permanently disabled, you can do so from Control Panel | Ease of Access Center | Make the mouse easier to use | Prevent windows from being automatically arranged when moved to the edge of the screen. (Note that this is a dreaded negative checkbox. It should have been phrased Arrange windows automatically when moved to the edge of the screen.) As a shortcut for those first three steps, you can hit the Windows key and then type better mouse into the Start menu search box, then click Change how your mouse works.