How do I get the screen size to show when Chrome console is open?
Known bug, already fixed: https://bugs.chromium.org/p/chromium/issues/detail?id=582421
It should land in M50. If you need it sooner then it is currently in Canary (side-by-side with standard Chromes) or you can use the Dev channel of Chrome.
Temporary solution:
1- Right click on html
element in Developer Tools(Elements)
2- Click inside website window