Groups of events are mainly for organising events. They can be collapsed and expanded using the arrow button in the title. They are edited with the Event Group dialog. To add an event group, right click an event or empty space in the event sheet and select Add group or press the G keyboard shortcut.
Events can be dragged and dropped in to and out of groups (be sure to drag from the event margin, and not from a condition or action). Entire groups can also be enabled or disabled with the Set Group Active system action, which is useful for situations like pausing the game. Disabling unnecessary groups can also help improve performance.
You can customise the event group header's colors by right-clicking and selecting Colors►Change text color or Colors►Change background color. To reset back to the default colors (which are based on the current theme), select Colors►Restore default colors.