Stacked tools do not show tab buttons Mac Qt 6.9.2

[goddard@…]

The following bug report has been submitted:
Platform:        macOS-15.6.1-arm64-arm-64bit
ChimeraX Version: 1.11.dev202510070157 (2025-10-07 01:57:14 UTC)
Description
When dragging and dropping Altloc tool on top of Model Panel the tabs don't show at the bottom of the stacked tools so I can't switch back to the Model Panel.  This is likely a Mac Qt 6.9.2 bug.  We saw it also with PySide 6 and Qt 6.9.2.

Sometimes the tabs do appear.  When dragging the Altloc tool (or probably any tool) if the underlying tool does not highlight gray then dropping Altloc will not show any tab buttons.  If the underlying tool does highlight gray then it will show tab buttons and all later drag and drops seem to work.  To reproduce this bug you often have to move the Altloc tool rapidly (e.g. 0.5 seconds) across the Log onto the Model Panel.  With a slow motion it works, with a fast motion it always seems to fail.

Log:
UCSF ChimeraX version: 1.11.dev202510070157 (2025-10-07)  
© 2016-2025 Regents of the University of California. All rights reserved.  
How to cite UCSF ChimeraX  

> ui tool show "Altloc Explorer"




OpenGL version: 4.1 Metal - 89.4
OpenGL renderer: Apple M2 Ultra
OpenGL vendor: Apple

Python: 3.11.9
Locale: en_US.UTF-8
Qt version: PyQt6 6.9.1, Qt 6.9.0
Qt runtime version: 6.9.2
Qt platform: cocoa
Hardware:

    Hardware Overview:

      Model Name: Mac Studio
      Model Identifier: Mac14,14
      Model Number: Z1800003VLL/A
      Chip: Apple M2 Ultra
      Total Number of Cores: 24 (16 performance and 8 efficiency)
      Memory: 64 GB
      System Firmware Version: 11881.140.96
      OS Loader Version: 11881.140.96

Software:

    System Software Overview:

      System Version: macOS 15.6.1 (24G90)
      Kernel Version: Darwin 24.6.0
      Time since boot: 48 days, 23 hours, 55 minutes

Graphics/Displays:

    Apple M2 Ultra:

      Chipset Model: Apple M2 Ultra
      Type: GPU
      Bus: Built-In
      Total Number of Cores: 60
      Vendor: Apple (0x106b)
      Metal Support: Metal 3
      Displays:
        PHL 278B1:
          Resolution: 3840 x 2160 (2160p/4K UHD 1 - Ultra High Definition)
          UI Looks like: 1920 x 1080 @ 60.00Hz
          Main Display: Yes
          Mirror: Off
          Online: Yes
          Rotation: Supported


Installed Packages:
    alabaster: 1.0.0
    appdirs: 1.4.4
    appnope: 0.1.4
    asttokens: 3.0.0
    babel: 2.17.0
    beautifulsoup4: 4.13.5
    blockdiag: 3.0.0
    blosc2: 3.9.1
    build: 1.3.0
    certifi: 2025.7.14
    cftime: 1.6.4.post1
    charset-normalizer: 3.4.3
    ChimeraX-AddCharge: 1.5.20
    ChimeraX-AddH: 2.2.8
    ChimeraX-AlignmentAlgorithms: 2.0.2
    ChimeraX-AlignmentHdrs: 3.6.1
    ChimeraX-AlignmentMatrices: 2.1
    ChimeraX-Alignments: 3.0.2
    ChimeraX-AlphaFold: 1.0.1
    ChimeraX-AltlocExplorer: 1.1.2
    ChimeraX-AmberInfo: 1.0
    ChimeraX-Aniso: 1.3.2
    ChimeraX-Arrays: 1.1
    ChimeraX-Atomic: 1.60.17
    ChimeraX-AtomicLibrary: 14.2
    ChimeraX-AtomSearch: 2.0.1
    ChimeraX-AxesPlanes: 2.4
    ChimeraX-BasicActions: 1.1.3
    ChimeraX-BILD: 1.0
    ChimeraX-BlastProtein: 3.0.0
    ChimeraX-Boltz: 1.1
    ChimeraX-BondRot: 2.0.4
    ChimeraX-BugReporter: 1.0.2
    ChimeraX-BuildStructure: 2.13.1
    ChimeraX-Bumps: 1.0
    ChimeraX-BundleBuilder: 1.6.0
    ChimeraX-ButtonPanel: 1.0.1
    ChimeraX-CageBuilder: 1.0.1
    ChimeraX-CellPack: 1.0
    ChimeraX-Centroids: 1.4
    ChimeraX-ChangeChains: 1.1
    ChimeraX-CheckWaters: 1.5
    ChimeraX-ChemGroup: 2.0.2
    ChimeraX-Clashes: 2.3
    ChimeraX-clix: 0.2.4
    ChimeraX-ColorActions: 1.0.5
    ChimeraX-ColorGlobe: 1.0
    ChimeraX-ColorKey: 1.5.8
    ChimeraX-CommandLine: 1.3.0
    ChimeraX-ConnectStructure: 2.0.1
    ChimeraX-Contacts: 1.0.1
    ChimeraX-Core: 1.11.dev202510070157
    ChimeraX-CoreFormats: 1.2
    ChimeraX-coulombic: 1.4.5
    ChimeraX-Crosslinks: 1.0
    ChimeraX-Crystal: 1.0
    ChimeraX-CrystalContacts: 1.0.1
    ChimeraX-DataFormats: 1.2.4
    ChimeraX-Dicom: 1.2.7
    ChimeraX-DistMonitor: 1.4.2
    ChimeraX-DockPrep: 1.1.4
    ChimeraX-Dssp: 2.0
    ChimeraX-EMDB-SFF: 1.0
    ChimeraX-ESMFold: 1.0
    ChimeraX-FileHistory: 1.0.1
    ChimeraX-FunctionKey: 1.0.1
    ChimeraX-Geometry: 1.3
    ChimeraX-gltf: 1.0
    ChimeraX-Graphics: 1.4.1
    ChimeraX-Hbonds: 2.5.3
    ChimeraX-Help: 1.3
    ChimeraX-HKCage: 1.3
    ChimeraX-IHM: 1.1
    ChimeraX-ImageFormats: 1.2
    ChimeraX-IMOD: 1.0
    ChimeraX-IO: 1.0.4
    ChimeraX-ItemsInspection: 1.0.1
    ChimeraX-IUPAC: 1.0
    ChimeraX-KVFinder: 1.7.1
    ChimeraX-Label: 1.2
    ChimeraX-ListInfo: 1.2.2
    ChimeraX-Log: 1.2.1
    ChimeraX-LookingGlass: 1.1
    ChimeraX-Maestro: 1.9.2
    ChimeraX-Map: 1.3
    ChimeraX-MapData: 2.0
    ChimeraX-MapEraser: 1.0.1
    ChimeraX-MapFilter: 2.0.1
    ChimeraX-MapFit: 2.0
    ChimeraX-MapSeries: 2.1.1
    ChimeraX-Markers: 1.0.1
    ChimeraX-Mask: 1.0.2
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    ChimeraX-MCopy: 1.0
    ChimeraX-MDcrds: 2.17.1
    ChimeraX-MedicalToolbar: 1.1
    ChimeraX-Meeting: 1.0.1
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    ChimeraX-MLP: 1.1.1
    ChimeraX-mmCIF: 2.16
    ChimeraX-MMTF: 2.2
    ChimeraX-ModelArchive: 1.0
    ChimeraX-Modeller: 1.5.22
    ChimeraX-ModelPanel: 1.6
    ChimeraX-ModelSeries: 1.0.1
    ChimeraX-Mol2: 2.0.3
    ChimeraX-Mole: 1.0
    ChimeraX-Morph: 1.0.2
    ChimeraX-MouseModes: 1.2
    ChimeraX-Movie: 1.0.1
    ChimeraX-MutationScores: 1.0
    ChimeraX-Neuron: 1.0
    ChimeraX-Nifti: 1.2
    ChimeraX-NMRSTAR: 1.0.2
    ChimeraX-NRRD: 1.2
    ChimeraX-Nucleotides: 2.0.3
    ChimeraX-OpenCommand: 1.15.1
    ChimeraX-OrthoPick: 1.0.1
    ChimeraX-PDB: 2.7.11
    ChimeraX-PDBBio: 1.0.1
    ChimeraX-PDBLibrary: 1.0.5
    ChimeraX-PDBMatrices: 1.0
    ChimeraX-PhenixUI: 1.3.9
    ChimeraX-PickBlobs: 1.0.1
    ChimeraX-Positions: 1.0
    ChimeraX-PresetMgr: 1.1.3
    ChimeraX-ProfileGrids: 1.4
    ChimeraX-PubChem: 2.2
    ChimeraX-ReadPbonds: 1.0.1
    ChimeraX-Registration: 1.1.2
    ChimeraX-RemoteControl: 1.0
    ChimeraX-RenderByAttr: 1.6.5
    ChimeraX-RenumberResidues: 1.1
    ChimeraX-ResidueFit: 1.0.1
    ChimeraX-RestServer: 1.3.1
    ChimeraX-RNALayout: 1.0
    ChimeraX-RotamerLibMgr: 4.0
    ChimeraX-RotamerLibsDunbrack: 2.0
    ChimeraX-RotamerLibsDynameomics: 2.0
    ChimeraX-RotamerLibsRichardson: 2.0
    ChimeraX-SaveCommand: 1.5.2
    ChimeraX-Scenes: 0.2.2
    ChimeraX-SchemeMgr: 1.0
    ChimeraX-SDF: 2.0.3
    ChimeraX-Segger: 1.0
    ChimeraX-Segment: 1.0.1
    ChimeraX-Segmentations: 3.5.10
    ChimeraX-SelInspector: 1.0
    ChimeraX-SeqView: 2.17.2
    ChimeraX-Shape: 1.1
    ChimeraX-Shell: 1.0.1
    ChimeraX-Shortcuts: 1.2.1
    ChimeraX-ShowSequences: 1.0.3
    ChimeraX-SideView: 1.0.1
    ChimeraX-SimilarStructures: 1.0.1
    ChimeraX-Smiles: 2.1.2
    ChimeraX-SmoothLines: 1.0
    ChimeraX-SpaceNavigator: 1.0
    ChimeraX-StdCommands: 1.19.1
    ChimeraX-STL: 1.0.1
    ChimeraX-Storm: 1.0
    ChimeraX-StructMeasure: 1.2.1
    ChimeraX-Struts: 1.0.1
    ChimeraX-Surface: 1.0.1
    ChimeraX-SwapAA: 2.0.1
    ChimeraX-SwapRes: 2.5.2
    ChimeraX-TapeMeasure: 1.0
    ChimeraX-TaskManager: 1.0
    ChimeraX-Test: 1.0
    ChimeraX-Toolbar: 1.2.3
    ChimeraX-ToolshedUtils: 1.2.4
    ChimeraX-Topography: 1.0
    ChimeraX-ToQuest: 1.0
    ChimeraX-Tug: 1.0.1
    ChimeraX-UI: 1.48.4
    ChimeraX-Umap: 1.0
    ChimeraX-uniprot: 2.3.1
    ChimeraX-UnitCell: 1.0.1
    ChimeraX-ViewDock: 1.5.1
    ChimeraX-VIPERdb: 1.0
    ChimeraX-Vive: 1.1
    ChimeraX-VolumeMenu: 1.0.1
    ChimeraX-vrml: 1.0
    ChimeraX-VTK: 1.0
    ChimeraX-WavefrontOBJ: 1.0
    ChimeraX-WebCam: 1.0.2
    ChimeraX-WebServices: 1.1.5
    ChimeraX-Zone: 1.0.1
    colorama: 0.4.6
    comm: 0.2.3
    contourpy: 1.3.3
    coverage: 7.10.7
    cxservices: 1.2.3
    cycler: 0.12.1
    Cython: 3.1.4
    debugpy: 1.8.17
    decorator: 5.2.1
    docutils: 0.21.2
    executing: 2.2.1
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    fonttools: 4.60.1
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    h5py: 3.14.0
    html2text: 2025.4.15
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    Jinja2: 3.1.6
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    MarkupSafe: 3.0.3
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[Tom Goddard]

The same problem was observed with PySide6 with Qt 6.9.2 reported as ChimeraX ticket #18657. Hopefully Qt 6.9.3 fixes it. Qt 6.9.3 was released September 30 but PyQt6-Qt6 still only provides Qt 6.9.2.

When trying to reproduce this bug sometimes ChimeraX crashed when moving the Altloc tool up down rapidly, reported as ticket #19077.

[Tom Goddard]

I tried commenting out our _Qt.float_changed() method that adjust floating window flags on Mac for instance to allow a floating window to stack behind the main window. That did not change the behavior in this bug report. It still some of the time shows the stacked window tabs and sometimes does not.

[Tom Goddard]

I tried PyQt 6.10.0 and the same bug where stacked tools don't show tabs occured. Also dragging the floating window back and forth quickly over docked tools caused the same crash as in #19077.

[Tom Goddard]

It often takes 2 or 3 tries dragging and dropping the Boltz tool in the same ChimeraX session before it fails to work correctly. But after it fails to work I have never seen it start working again in the same session.

[Tom Goddard]

I installed PyQt 6.8.1 in my current ChimeraX devel build and it does not have this problem, nor does it crash if I rapidly drag the floating window over docked windows. So it seems that the bug was certainly introduced in Qt 6.9.x.