ChimeraX Developer Meeting

Attendance: Zach, Greg, Tom, Eric

September 22, 2025

Agenda

• Chimera not working with macOS 26. Togl problem and PyOpenGL problem.
• Updating prereqs.
• Work in progress reports
• Inside ribbon color?
• Make Chimera end-of-life bug report and registration changes.
• Back up the Chimera build machine to a solid state drive, Windows 7.
• Linux ARM64 release and download page

---

Discussion

• Chimera broken on macOS 26
  • Chimera on macOS 26 (released a week ago) is showing the graphics pane covering the command-line and status line, with an empty space at the top of the Chimera window of the same height as command-line and status line.
  • Might be that the graphics is failing to draw the right rectangle in the main Chimera window. Or it might be that it is drawing on the wrong window (the main window instead of the graphics pane subwindow).
  • The problem is probably in Togl the Tk OpenGL package. Greg used to maintain this since the original developer abandoned it decades ago.
  • Greg thinks the deprecated setAglDrawable() call done in Togl many no longer function. He found a page that says it is superceded by setAglWindowRef().
  • Eric will try putting debugging statements in the togl.c code on essex2 the Mac Chimera build machine, then copy the togl library to euclid which is running macOS 26 (updated today) for testing.

• Chimera 2d labels broken on macOS 26
  • Chimera uses PyOpenGL for 2D labels and fails importing PyOpenGL on macOS 26.
  • Appears it cannot fine the Mac OpenGL library.
  • Tom will try to fix this.
  • Fixed it right after group meeting. Chimera had a patch for Mac PyOpenGL to hard code the correct OpenGL path but it was only being used from macOS version 11 or 10.16 as reported by Python. I think Python reported all previous macOS versions as 10.16 or 11. But now it is reporting 26.0.

• PySide 6 bug fixes
  • Zach has fixed some of the PySide bugs in ChimeraX such as links in the Log not working.
  • The crash opening Modeller tool happens when the AlignmentItemList is added. Other ItemList subclasses in other tools do not crash. Need to find what is special about this AlignmentItemList or what is special about how it is placed in the tool.
  • Floating windows with status lines such as Render by Attribute crash when closed. After meeting Zach found this happens when the QWindow for the status line reference count drops to zero. Needs some fix.

---

Action Items