I personally find this Dell mouse stick pointer very annoying.  It always messes 
up my typing.  Thus I always had it disabled. 
All of a sudden, today it is enabled.  It turns out that Dell Touchpad application no longer exists 
in my laptop.  I don't understand how and why this could happen.  It could be related to Windows update.  
In order to disable it, I 
have to re-install Dell Touchpad application.  After the reboot, 
Dell Touchpad will show up in 
Mouse Properties so that I can configure it.  
The following is the procedure of how to disable this 
mouse stick pointer.
- If you don't have Dell Touchpad application installed, go Dell Support site to download and install it. Most of time, a reboot is required after installation.
- Go Control Panel.
- Select All Control Panel Items.
 
 Or type mouse at the search box and then select Change mouse settings.
 
 
- If you have Dell Touchpad application installed, 
Dell Touchpad tab will show up. Click on the image inside the Dell Touchpad tab content.
 
 
- Select Button Settings from Dell Touchpad window.
 
 
- Select Device Select tab and click Disable radio button of Pointing Stick 
and then click Apply.
 
- The mouse stick pointer will be disabled instantly. Click OK and then exit the Dell Touchpad application.
Note that the above procedure/pictures are captured from my Latitude E6510.