Save custom properties to grease pencil datablock ?

Coding Python Support
1

Is it possible to save properties to grease pencil data?

bpy.data.grease_pencil[‘GPencil’][‘prop’] = my_prop is working for the current scene but once I reopen the file after Blender was closed, the property doesn’t exists anymore.

I’d like also to do something similar to GP layers. Is that possible?

2

I have the same behavior if I register the property with bpy.types.GreasePencil.my_prop = bpy.props.StringProperty(…)

bpy.data.grease_pencil[‘GPencil’].my_prop = “prop” is working but not saved if I open the file again.

Is it a bug or something that is not allowed?

3

I’m also facing this problem. I try to create custom properties into GPencilLayer() and it seams that this feature is not supported. I think that this should be supported and if someone could point me into right direction, I could try to code this into blender.