The Position button lets you to change the position of the texture on the object. Do not confuse this with aligning individual maps within a single surface texture definition. To align individual maps, click the Compose Maps button at the bottom of the Surface texture editing dialog.
When you click the Position button, the tool palette changes. Tools are provided for moving, rotating or scaling textures on the object. Handles appear on the selected object. You can move, rotate, or scale the texture as desired.
Use the Shaded view option to position textures. Also, the Show Textures option must be enabled on the Windows tab of the Preferences dialog.
NOTE: You cannot edit the placement of a texture with UV mapping, so handles won't be available with this mapping style. However, you can change the mapping style at any time.