Selection grid eating framerate

[Jigoku]

I forget what the command that sets this is, but when you press tab twice to get this grid selection style:

Note the fps, it also worsens the smaller the gridpower and consequently ends up washed out with the glow effect the smaller you go.

[Jigoku]

Can also occur with the default selection grid style:

[qreeves]

I daresay some of this is due to the extreme amount of overdraw, as the code doesn't really check if a line has already been drawn in that position when it moves to the neighbouring outline.