[v2] GuiOn.... Topic is solved

[jNizM]

OnEvent
OnNotify
OnCommand

Should be visible on the left side under Graphical User Interfaces in the overview like OnMessage
Only came across these useful functions by chance.

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In addition, there should also be an overview for Graphical User Interfaces like for Drive with a small info.

[Ragnar]

Changes added in PR #492.

[kczx3]

Great suggestions!