Title bar is tiny on a high-DPI monitor

[Aaron Avery]

I'm currently on a 4K monitor set to 200% scaling.
Join's minimize and close controls are tiny and very hard to hit with the mouse.
The version string is also quite small, and I think the refresh icon is smaller than intended, since it's half the height of all other icons on that row.
I believe the rest of the icons are the correct size (app icon, tabs, and Google user avatar).

I'm familiar with how to get high-DPI working correctly on Win10 (manifest settings, etc.) if you want help.