[Gimp-user] Help: How to activate pen pressure for varying brush size? (Tablet users)

[siehorse <forums gimpusers com>]

I have downloaded GIMP version 2.6.11 for my Mac OSx and am using a Wacom Intuos tablet. 

I have gone to Edit > Preferences > Input Devices > Configure Extended Input Devices and set the "pen" option 
to "Screen." The "pressure" is set to "3." 

When using the paintbrush tool, there is no variance in the brush size as I press my pen harder/softer. 
However, there IS variance in brush opacity. I know my tablet/pen works fine because there is pressure 
sensitivity in my other tablet-responsive programs. 

How can I get my strokes to taper/grow accordingly to my pen pressure?

Thank you for your help!

Cheers, siehorse

-- 
siehorse (via gimpusers.com)