Yep, this is still a problem...
Using XMir my options are limited:
XMIR-0 connected primary 1366x768+0+0 (normal left inverted right x axis y axis) 280mm x 160mm 1366x768 59.8*+
Compared to native X:
LVDS1 connected primary 1366x768+0+0 (normal left inverted right x axis y axis) 277mm x 156mm 1366x768 60.0*+ 1360x768 59.8 60.0 1024x768 60.0 800x600 60.3 56.2 640x480 59.9
Yep, this is still a problem...
Using XMir my options are limited:
XMIR-0 connected primary 1366x768+0+0 (normal left inverted right x axis y axis) 280mm x 160mm
1366x768 59.8*+
Compared to native X:
LVDS1 connected primary 1366x768+0+0 (normal left inverted right x axis y axis) 277mm x 156mm
1366x768 60.0*+
1360x768 59.8 60.0
1024x768 60.0
800x600 60.3 56.2
640x480 59.9