Hans, in DPX the Help file mentions this under 'Shape Builder'
Nib Size
There is a selection of 6 preset nib sizes on the Infobar. The nib size changes, relative to the objects on the page, as you change the zoom. In other words, as you zoom in, because the nib remains the same size on screen, it allows smaller details to be erased. While in the tool, you can press keys 1-6 to quickly select the different nib sizes.
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