
This reverts commit c0c027c608d0aa1c547a2a82bd3ce6b84bb83b83. Because for some reason animating external opacity and position is still incurring internal repaints, which disables offscreening and makes fading of overlapping actors look wrong. `ON_IDLE` should be fixed in mutter before it is used (in boxpointer at least) again. Fixes https://gitlab.gnome.org/GNOME/gnome-shell/issues/2270