Operating system: Linux-5.10.16-artix1-1-x86_64-with-glibc2.33 64 Bits
Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 460.39
Broken: version: 2.93.0 Alpha, branch: master, commit date: 2021-02-18 23:56, hash: rB4604350eefab
Short description of error
3d cursor with snap to vertex enabled will not snap to grease pencil points/vertex.
-This is unexpected as the 3d cursor with snap to vertex enabled will snap to all other vertex/point types including bezier, path and poly curves converted from grease pencil.
Exact steps for others to reproduce the error
From default cube scene:
go to snapping ui, enable snap to vertex, enable snapping during transform, (click magnet icon or hotkey shift+tab)
add a blank grease pencil object to scene:
shift+A choose grease pencil>blank
select draw mode, draw a stroke.
choose cursor tool or use shift+right-click to place cursor:
drag cursor over grease pencil stroke, it does not snap to any points related to grease pencil.
next convert grease pencil stroke to other curve object types, the cursor will snap to those object types' points/vertex:
leave draw mode and go to object mode of grease pencil object.
Select and move the Path object (named GP_Layer) from outliner, so you can see it separately from grease pencil stroke.
See that the 3d cursor will snap to the Path object. Repeat the Convert steps with Bezier and Poly Curve object types. They snap as expected.
A .blend file is attached with each of the different object types converted and snapping enabled.