What are the region-space combinations that can be used for button and panel registration What are the available regions, and also, which ones can have a button registered to?



While registering any panel we need to specify which space/region should be assigned to, in example: {space: VIEW_3D, region: UI}.

However not all regions are available for every space, and not all regions could have buttons/panels registered to them.
This table has all the space-region combinations that work.



Reference: Blender Space-Regions guide