When you select "Island" from the Map type drop-down menu and then reset the changes, Map type is reset back to Normal but the GUI below still acts like it's set to Island (i.e., Coverage is grayed out). It's easy to correct by selecting Normal.
Pastebin: https://pastebin.com/KEEvGiWz
[0.17.0] [kovarex] Map reset doesn't reset Island
Re: [0.17.0] [kovarex] Map reset doesn't reset Island
Thanks for the report, fixed for 0.17.2