Only a handful of people have traveled to such staggering depths. One of them is movie director James Cameron, who using a state-of-the-art vessel, dropped 35,000 feet, or about 7 miles, to the deepest place on Earth -- the Challenger Deep in the western Pacific Ocean.
DPI stands for dots per inch. Depending on the mouse make it will have certain presets (e.g 3000, 6000) and pressing it will cause your mouse to cycle through them. The higher the DPI , the farther the cursor on your screen will move when you move the mouse.
A tooltip control can be either active or inactive. When it is active, the tooltip text appears when the mouse pointer is on a tool. When it is inactive, the tooltip text does not appear, even if the pointer is on a tool. The TTM_ACTIVATE message activates and deactivates a tooltip control.