Canvas.Activate
From Xojo Documentation
Event
The control is activated. In a single window interface, the Activate event fires when the parent window is activated. See the Application and Window Activate events.
Notes
This can be because the app is launched or a window belonging to another app is no longer frontmost (active). The Deactivate event fires when another window becomes active. In a single window interface, the Activate event fires when the window is activated, e.g., when the app first displays the window.