Hi, I've also had the same display issues on new Mac OS Tahoe with Chimera 1.19. ChimeraX seems to work just fine. This is a quick fix that works for now for Chimera display issues: Work around Chimera issue (no GPU OpenGL) This avoids the bad OpenGL layering. In Terminal: /Applications/Chimera.app/Contents/MacOS/chimera --nomultisample or /Applications/Chimera.app/Contents/MacOS/chimera --bgopacity Those sometimes fix window artifacts by disabling transparent background blending. If you want to make it permanent: 1. Open Terminal 2. Create a small wrapper: echo '/Applications/Chimera.app/Contents/MacOS/chimera --nomultisample' > ~/chimera_fix.sh chmod +x ~/chimera_fix.sh 3. Run ~/chimera_fix.sh to start Chimera cleanly each time. Looking forward to a proper fix... Thank you! -Almutasem Saleh