27c954386b
This was introduced in the original implementation of weightpaint
in 2.8 (20f95de6ba). But this is very shortsighted, we can't assume only one
object will be edited at once, nor should we tag things during drawing.
There is a chance this introduces "bugs". If it does, we then tackle them in the
proper way (usually tagging DEG after operators changing the weight paint data).