set/get property for individual region_3d or space_data

Hi… I’m trying to implement a undo/redo viewport system, it’s working already, but for one view3d only. I want to get individual undo list for each opened view3d.

My system use set/get properties in scene object like this -> context.scene[‘undo_list’] = [undo1, undo2, undo3, …]. but this not working for space_data or region_3d object… context.space_data[‘var’] = ‘zzz’ don’t work.

someone know how to set/get properties for individual view3d panel??

thank you.

I’m beginner on blender, if have another way to go I can search on google, api doc etc. Welcome any suggestion.