STEPS TO REPRODUCE 1. Use any brush. All OK. 2. Turn the pen and use the eraser. It works. 3. Turn the pen and use that brush. Nothing happens. If you use the eraser again, it works. If you use another brush, it works. The first brush is still not working. OBSERVED RESULT After the first use of the eraser, the brush doesn't work. EXPECTED RESULT Brushes and eraser work. SOFTWARE/OS VERSIONS Krita Version: 4.2.9 Languages: ru_RU, ru, en_US, en Hidpi: true Qt Version (compiled): 5.12.7 Version (loaded): 5.12.7 OS Information CPU: x86_64 Kernel Type: winnt Kernel Version: 10.0.18363 Product Type: windows Product Version: 10 ADDITIONAL INFORMATION I use a pen from Wacom Cintiq.
You need to set the opacity to something bigger than 0 and it will work from then on. The bug is known already, so I'm closing this bug report. *** This bug has been marked as a duplicate of bug 389022 ***