Selectors for properties `space_object` and `space_subtarget` are missing in Shrinkwrap constraint UI panel. This was because of the difference between property names it didn't use `space_template` to create those selectors. Since this is just a single special case, a branch was added in `draw_shrinkwrap` in similar fashion to display those selectors. Pull Request: https://projects.blender.org/blender/blender/pulls/128347