Fast marching problem ver 5.0.2

Operating system: Windows 10
Slicer version: 5.0.2
I use this version and install Fast Marching but this extension is not appeared in “Segment Editor”, its interface is quite different from this video Fast marching segmentation in 3D Slicer - YouTube
So how can I solve this problem?
In addition, I want to measure mastoid air cells, middle ear spaces in temporal bone CT scan, any suggestions to do this? because the mastoid air cells are separated by bone septa so I think they’re difficult to measure the volume.
Thanks so much for your help

Fast marching effect works exactly the same as it is shown in the video. There was a minor change in the Segment Editor module layout in that the toolbar is now vertical, while previously it was horizontal:

Note that the Fast Marching effect is provided by SegmentEditorExtraEffects extension, so you need to install this extension to make the effect show up in Segment Editor.

I would recommend to create a new topic for your segmentation question, describing what you want to segment, what you have tried so far, and how it worked; illustrated by screenshots.