This patch disables viewport shading during creation of the image projection for external image editing, since the user almost certainly wants to just edit the existing texture.
Here is the revised patch, with the changes you suggested.
Note that my python properities (project_non_renderable, and project_shading)
col.prop(ipaint, "use_occlude") col.prop(ipaint, "use_backface_culling") col.prop(ipaint, "project_non_renderable") col.prop(ipaint, "project_shading")
aren't showing up in the options toolbar and currently I'm a bit too tired to figure it out :)