This one adresses the remaining comments by @JulienKaspar in D11498,
namely:
- sync to the active texture paint slot when changing image in the Image
Editor
- sync to the active image node when changing image in the Image Editor
- do all syncing from this patch & D11497 & D11498 to the texture paint
canvas (aka. Texture Slot "Single Image" mode - as opposed to "Material"
mode) as well. (this could be split in a separate commit)
This also has the benefit of all materials (and objects) using the
texture we are currently painting actually updating in the viewport when
changing the texture in any of the editors.
ref T88788
ref D11496
ref D11497
ref D11498