I'm running the latest Arduino but the problem has been around for a while now. I guess the old phrase "a picture is better than a thousand words" is appropriate. I tried changing the application font in "Appearance" settings and tried a different Theme, but neither had any impact. See the enclosed images for an example of the problem.
The selected items in your screenshots are perfectly readable.
Here's the relevant bug report:
Note that the suggested fix:
one possible workaround for @LightningStalker might involve editing the arduino start script. Deleting "-Dswing.defaultlaf=com.sun.java.swing.plaf.gtk.GTKLookAndFeel" might cause the JRE to revert to some Java default rendering that looks wrong for Mint, but probably doesn't suffer from low contrast color choices.
Is no longer relevant. That option was removed from the arduino script before the release of Arduino IDE, so it evidently was not a fix for AverageGuy.
AverageGuy's board.png:
Note that the selection in the menu should say "Generic ESP8266 Module", but is instead just a white space.
pert:
Note that the selection in the menu should say "Generic ESP8266 Module", but is instead just a white space.
Ah, missed that on my cell phone 
I still have the problem. It's also a problem with Mint Mate 18.
Jim.
I started messing around with different themes. (Control Panel->Appearance) None of the standard themes fixed the problem so I went hunting for other themes. Mint 19 finally works OK with "Ant" theme and Mint 18 works OK with BlueMenta. I fixed Mint 18 first and tried BlueMenta on Mint 19 but it didn't look very good so I finally found "Ant". A lot of the themes are dark and my eyes just don't work when things appear in dark blue or red on a black background, so I avoid them.