Never mind my question about the brushes - I now understand what you meant.
Would be helpful to be able to edit/delete posts here. EDIT: Hey, now I can edit - looks like it's only possible after the fifth post.
Thank you! Seems like we posted at the same time.
Yes, I'm left-clicking the field.
My machine is an Intel i7-3930K with an NVIDIA GTX 980 Ti and 32GB RAM.
Blender, MODO, Maya, Houdini and NUKE run just fine with it on Linux, as well as ZBrush on Windows - so it shouldn't be the hardware that's holding things back here.