So, I am trying to model over the top of some Google Earth data. I have my model in edit mode with the Google Earth mesh ‘selectable’ value unchecked in Object Properties > Visibility. In my snap settings I have ‘Exclude Non-Selectable’ enabled, but when I use the measure tool it still snaps to that underlying mesh. If I hide the reference mesh my snapping works as expected.
Is this a known bug, or am I simply not using my snap settings correctly?
I tried this in 3.3.1 with a visible but unselectable cube and a plane, trying to snap a vertex of the plane to the cube, with the exact same snapping options you show, and it does not snap. Which means this works as expected.
So if there is a bug, it’s a non-obvious one. I usually suspect user error first though. 
Is the .blend file humongous, or can you share it?
Thank you, and I agree…it’s usually on me. lol.
I can’t share the file, however it seems that this is affecting the measure tool only. I was wrong on the vertex snapping. Now that I rechecked, I do believe the vertices are snapping correctly.
I filed a bug report on Blender’s site. Can you check if the measure tool ignores it for you?
Yup, the measure tool ignores the snap settings and snaps to unselectable objects for me as well. AFAIK it has done so in previous versions too… lemme check… yeah, in 3.1.2 the measure tool also snaps to unselectable objects.
This might have been intended behaviour, and I can see why one might want it to be so, at least in older versions. But since we now have the new option to ignore unselectable objects, the measure tool should probably obey that as well.
Yeah, that’s my thoughts as well. I feel like if an object is set to not be selectable, nothing should interact with it unless you select it via the outliner.
I also just noticed that if you are creating cubes interactively they snap to all meshes as well. I’d expect that to work as well. It really makes things more difficult for retopologizing or using 3d reference.
I kinda understand why the measure could snap to unselectable objects before there was a constraining snapping option for that – you might actually have good reason to measure between a selectable and an unselectable object, and it would be pretty annoying to have to temporarily make the object selectable just for a measurement – after all, measuring doesn’t change anything, so there’s no harm done.
But now that we have that snapping constraint, I think measuring should be consistent with it.
Interesting about the interactive cubes! Good thinking trying those. Yeah, they should also obey the snapping constraint IMO. Definitely report it, then we’ll find out whether this was just overlooked or was a conscious design decision.
Yeah, I can see why the measure tool would just snap to everything. I can give it a pass, even though I want full control. Totally understand that until recently we didn’t have the “exclude non-selectable” option as well, so this is a new situation.
I think I’ll add the interactive cubes to the list, or file a new bug report on that. I’m keen to hear if it was a conscious decision or if they simply haven’t had time to address the way the new “exclude” option works in snap settings.