When I resize the brushes the transitions are lagging, are slow. This no happen on Krita 2.9 at the same Computer. I use LinuxMint 18 Cinnamon Reproducible: Always Steps to Reproduce: 1. Resize brush and see the lag 2. 3.
Carlos, this bug has been fixed on the latest stable version 3.0.1.1, here are the notes and downloads https://krita.org/en/item/new-stable-and-development-builds/
I updated my instalation to krita 3.0.1-1 and this work perfect!! thank you!!