mintty window border?

[Jim Garrison]

Mintty's window does not seem to have any border at the left and bottom.
The top of the window has the title menu bar and the right side is the
scroll bar.  When I have multiple mintty windows open, and they overlap,
since there is no border, one window blends into another.

I searched mintty's options and there doesn't seem to be a way to
specify a border.  If the window background is a light color, there's
a subtle drop shadow that helps a bit, but with a dark style it's
impossible to distinguish the windows.

Here's a sample:
https://drive.google.com/file/d/10zKWdie_nA-_hzsN8i_GeCw7VadJBmol/view?usp=sharing

Is there a way to make it draw a border?

-- 
Jim Garrison
jhg@acm.org