A fix is available here:
https://github.com/fbudin69500/Slicer/tree/mantis-0003973-libvtkViewsQt-6.2.1-not-packaged and a pull-request has been made here:
https://github.com/Slicer/Slicer/pull/242

See https://github.com/Slicer/Slicer/pull/242#issuecomment-77467553

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Thanks for your patch.

As indicated in commit r23766 reverting r23755 , I wonder if a similar approach could be applied.

I would like to check if your extension requires this component explicitly or if there is find_package(VTK ...) in your extension that doesn't account for the VTK component provided by Slicer.

If you run WhatModulesVTK.py in your extension source dir ... is vtkViewsQt listed ?

Running command like this should give the answer:

/path/to/VTKv6/Utilities/Maintenance/WhatModulesITK.py /path/to/VTKv6 /path/to/extension-src-dir

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Resolving this issue since as of r24684, the library is packaged:

$ cd /Users/kitware/Dashboards/Nightly/Slicer-0-build/Slicer-build/_CPack_Packages/macosx-amd64/DragNDrop/Slicer-4.4.0-2015-10-30-macosx-amd64/Slicer.app/Contents>
$ find . | grep libvtkViewsQt
./lib/Slicer-4.4/libvtkViewsQt-6.3.1.dylib

Fixed in r24029
See http://viewvc.slicer.org/viewvc.cgi/Slicer4?view=revision&revision=24029