Check this box if you don’t want to see ToothFairy’s icon in your Dock. You will still be able to access ToothFairy’s preferences by Control-clicking on any of the device icons in the menu bar.
Why do I see the Dock icon even after hiding it?
After you’ve checked the Hide Dock icon preference, you need to quit and relaunch ToothFairy in order for the change to take effect.
Also, macOS 10.14 and later include a section of the Dock for recent applications, and this can include the icons even of applications that have hidden their icons. To hide ToothFairy from this section, first quit ToothFairy. Then you can either:
Click and hold on the ToothFairy Dock icon and choose Options ‣ Remove from Dock from the menu; or
Drag the ToothFairy icon off the Dock; or
Go to System Settings ‣ Dock & Menu Bar ‣ Dock & Menu Bar and uncheck Show recent applications in Dock to hide that section entirely.
Note: On macOS 10.15 and earlier, this is in System Preferences ‣ Dock ‣ Show recent applications in Dock.