The active property of GUI elements prevents mouse events from firing – this is especially useful when we don’t want the camera to zoom while we’re scrolling through a ScrollingFrame with the mouse wheel, don’t want our selection to be cleared when we left-mouse-click on a button, and in other similar scenarios. The context menu has eluded this feature though, and it is still opened when you right click on a GUI element with active set to true – this prevents any sort of easily-accessible context menus from being used in plugins.
The main reason the animation editor is so counterintuitive to use is because of the lack of context menus due to this exemption, and other plugins have made a mess of themselves trying to work around this. The context menu should not be exempt from active GUI elements and active GUI elements should intercept right mouse button clicks like they do for every other mouse event so we can use right mouse click context menus in our plugin GUIs.