ChimeraX Developer Meeting

Attendance: Zach, Eric, Tom, Greg

April 27, 2026

Agenda

• DLL load failed: An Application Control policy has blocked this file #20228.
• Graphics impostors for atoms and bonds.
• Release candidates start May 4.
• Inside ribbon color?
• Toolshed reduce query result size.
• ​Residue notes in mmCIF, Oliver Clarke
• Chimera not working with macOS 26, graphics pane positioned over command-line.
• Work in progress reports
• Make Chimera end-of-life bug report and registration changes.

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Discussion

• DLL load failed: An Application Control policy has blocked this file #20228.
  • Have 10 reports of this error all on Windows 11, build 26200, 9 reports in the last 2 weeks.
  • Seems to be caused by some Windows 11 update.
  • A half-dozen different dlls were reported to fail to load, mmcif, ribbon, surface, smith waterman, ....
  • Search online suggest Windows Smart App Control or Windows Defender Application Control.
  • vizvault Windows 11 build 26200 does not have this problem, nor does Greg's home machine.
  • Only one report had a use email address and they did not respond.
  • Hope is we get an email address of someone who can check various settings to find what is causing the DLL loads to be blocked.

• Release candidates start May 4
  • Everyone is still ok with starting release candidates in 1 week.

• Graphics impostors for atoms and bonds
  • Zach tried imposter rendering of atoms (and maybe bonds).
  • Can be faster and give smoother appearance but uses more complex code.
  • Tom says he does not think the performance improvements justify the extra complexity and unknown future maintenance. Also upset that this was worked on without prior discussion.
  • Eric asked about supporting current triangle-based rendering of spheres and imposter fragment rendering.
  • Zach said he is fine if impostor code does not go in, but that Scooter and Tom Ferrin suggested this optimization.

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Action Items