Glitches if using --with-no-title-bars (and Metal?)

[vemv]

Hi,

I've used --with-no-title-bars over a year with no issue.

Recently I got a new Macbook Pro, and started using Mojave/Metal accordingly (before I stuck to High Sierra + Macbook Air).

After these updates, If a line is long enough to cause horizontal scrolling, I'll see glitches:

All I'm doing is pressing the left/right arrow keys, no other commands triggered. And yet the rendered characters get scrambled.

I suspect this is directly related to Metal - could you add a Metal flag so I can confirm?

Thanks - Victor

[vemv]

(Can confirm that the issue is exclusive to this distro and the --with-no-title-bars flag: works fine without the flag, or using the emacsformacosx distro)