- blue = non-boolean item (list of choices or values without boolean meaning)
- green circle = boolean item (ON/OFF)
- green square = OFF, option A, option B etc (can be interpreted as boolean item)
- grouping submenus also have a boolean value (green square if anything from there is enabled)
- ON/OFF in main menu, options in submenu: useful to toggle the option on and off quickly, keeping the previous settings
- pickbox: when there's nothing to adjust (just pick an option)
- text case: it was suggested to make all items lowercase
- play button: it was used in the old days to decrement the value (historically, navigation keys were just arrows and SET, didn't know what to pick for decrement and didn't know how to handle the scrollwheel, so I just picked PLAY); never used it lately (actions are triggered with SET); can be reallocated.
- PLAY is also a hotkey introduced by mlv_play; didn't realize it also works from the ML menu (never tried).
This stuff was discussed in detail at
https://www.magiclantern.fm/forum/index.php?topic=4386.0Reference:
https://www.magiclantern.fm/forum/index.php?topic=10422.0