Compatibility with transient-mark-mode (highlighting the selection) about macrostep HOT 4 CLOSED

@joddie I made a fix for this in #16, and it seems to work.

Though one of the tests (macrostep-expand-and-collapse) did fail for a naive fix shown here. Where is the priority property used outside of checking if it's equal to 1?

from macrostep.

Yes, the priority overlay property has a special meaning to Emacs: when there are several overlays at a point, all with different values for SOME-PROPERTY, priority determines which of them overrides the other. See the Elisp manual node "Overlay Properties".

I think your PR is probably good but I have a couple of questions which I will ask over there.

from macrostep.

Forgot to add: macrostep needs to be able to determine the innermost overlay when there are multiple levels of expansion. This is done by setting priority to higher values for each successive level of expansion, which explains why the expand-and-collapse test would fail without ti.

from macrostep.

Right, I was searching around in macrostep.el for explicit uses of priority and somehow thought that since it seemed to work in trivial cases that it wasn't actually being used as normal. My bad.

from macrostep.