This particular issue was already present in r27104 when the VTK version was updated to include fixed in VTK to avoid workaround associated with 0003808.

This can be verified by downloading the installer associated with r27120: https://download.slicer.org/bitstream/788001

On windows:

Installer associated with r27099:

• https://download.slicer.org/bitstream/785311
• Qt5, VTK9
• It works well

Installer associated with r27105:

• https://download.slicer.org/bitstream/785900
• Qt5, VTK9
• Does NOT work

Workaround is to pan before grabbing fiducials as describe here:

https://github.com/pieper/LandmarkRegistration/pull/24#issuecomment-440787136

With the pan workaround as a clue, I can (sometimes) reproduce this without using the landmark registration module

1. Load volume
2. Place 1 or 2 fiducials
3. In markups module, activate Jump to Slices and Centered
4. Jump to a fiducial
5. Try to move fiducial. It will usually be immovable in at least 1 view

That's a huge help - thanks!

This will need some deep dive debugging to keep track of all the picker code and whatnot. In the previous version of this bug I spent several days on it. Getting a pure-VTK demo was key to getting it fixed that time and would be good this time too if we can do it.

Working to get this fixed:

Thanks for the update. This will be a good candidate for the 4.10.2 patch release.

Worth noting that since this morning, the widget changes of @lassoan and @Davide have been integrated into master. See r27974

Fix finalized in 4.10.2 release branch: http://viewvc.slicer.org/viewvc.cgi/Slicer4?view=revision&revision=28255