Hi anywhere-final,
Thanks for the information and demo of the problem.
I typically try to avoid these wild guess listings, as I think it is better to explore the file and provide a clear reply. Hence, I don't ask for videos or images; it is always the file.
If the selection is done, can you move the polygons up (P.Y) while the one in question stays?
For example, Select this as in your movie,
It looks like not all are selected, but one can move those. But moving it shows that it is selected. Switching on Normals in the Attribute Manager> Viewing Settings> View might help solve this secret.
I get the idea of the problem, but I have no idea about the geometry and its cause.
If you can share it via WeTransfer, I'm happy to take a look at it.
Here are some random tips; again, I'm unclear what the underlying problem is. (Considering that Polygons belong to the selected Object)
• Main Menu> Select> Select Connected (U~W)
• Attribute Manager> Modeling> Mesh Checking
• Main Menu> Mesh> Remove> Optimize. (U~O)
• Main Menu> Selection> Hide selected –– then explore how selectable the remainder of polygons are.
• Copy the model into a new project file, and explore again, while also checking the Main Menu> Window> Structure manager, set to polygons might help
• Select Point mode, then Shift-Click on the Polygon Icon. Any luck?
This list could go on much longer, but that is what I try to avoid here, and explore it based on a model
Enjoy your Sunday