The minimap button allows you to perform various actions using a variety of click and key combinations. Here is a list of them.
Left-click - Toggles the options panel.
Right-click - Toggles error frame messages. If you are using the 'Hide error messages' option (text menu), right-clicking the minimap button will allow you to see error messages temporarily. The minimap button will be colored red while error messages are showing.
SHIFT and left-click - Toggles the in-game music setting. If you like to listen to the game music sometimes, but not all the time, this is for you.
SHIFT and right-click - Toggles the coordinates frame. If you are using the coordinates option (interface menu), hold down SHIFT and right-click the minimap button to toggle the coordinates frame. This is useful for conserving CPU power as the coordinates are not updated while hidden.
CTRL and left-click - Toggles the minimap target tracking feature. This is useful as it allows you to quickly activate target tracking when needed, such as when NPCscan fires an alert that a rare spawn is nearby. Click the NPCscan alert then activate target tracking to pinpoint the rare spawn.
CTRL and SHIFT and left-click - Toggles the Zygor addon state (if installed). Zygor is very useful but it has a massive resource footprint and can cause FPS drops, stuttering and tainting. Completely disabling the addon prevents these issues. Using this click modifier will reload your UI.
CTRL and SHIFT and right-click - Toggles between windowed-maximised and windowed non-maximised video modes. This is useful for people who like to switch between modes regularly. True fullscreen mode is not supported.