I'm using Unity on my Dell XPS 13 2015 but wanted to switch to the latest version of cinnamon. Therefore I added the corresponding repositories and installed cinnamon.
After changing the desktop environment I got some problems with Cinnamon and movoed back to Unity and removed Cinnamon.
As you can see in the screenshot below, the windows, sidebar etc. looks normal but the buttons and fonts are not scaled proportionally to the rest.
Changing the scaling in the options results on smaller fonts and buttons but the windows become too tiny.