blender viewport is rotating around an unknown point In blender 2.73 , when i scroll with my  MBP trackpad to rotate around my cube , it does not rotate around the cube as center. but it rotates around another point not too far from the cube. 

I checked online for how to set pivot points and found menu->object-> transform->geometry_to_origin,  and a few more options , but the rotation point is still not the center of the cube itself.the only way for me to get back to normal  is to close this file and open a new file from start. 

i want to rotate the view , with the cube as center , just as it did when you open a new file. what is the trick to fix this ?
To make the viewport rotate around the selected object go to User Preferences and check Rotate Around Selection: