I was recently installing a new machine and getting a strange feeling that something was awry with my IntelliJ fonts. They looked like they were not being anti-aliased, even though I had checked the correct option. Also I noticed that generally fonts were looking a bit ropey.
After some puzzling I discovered the dialog above. If you right click on the desktop then to properties->appearance->effects… you will see it and you need to make sure the font smoothing is checked.
Phew, now I have beautiful code again.