2 things that bother me

What does the gem do in the botum right corner of the Editor and is there any way to make the Editor stop switching between night and day while i'm making my map? + rep to whoever can answer this.

Go into "preferences" and in one of the tabs there's an option to use a fixed time of day. Either that or in Map Options you can set a fixed time of day.

When the Gem is activated, whenever you delete a unit/destructible it will play its death animation in the editor. Also, if you click on units a lot they will say things.

If you click the gem too much it yells at you, also if you're using an insane number of preplaced units (and some doodads), it will help you stay sane for a little bit longer.

Just press "L", which is the hotkey that toggles whether Lights show up (night/day).

Same with "P" for Pathing, "N" for Naval Pathing, "W" for Water, "S" for Shadows... Just check the top toolbar, "View", it has a bunch.