OK, I found what is breaking the logic in the
Show(Point) Positions the `ToolStripDropDown` relative to the specified screen location.
So the ContextMenuStrip, to my surprise, takes the screen coordinates, not the Form ones. I then just removed
PointToClient and everything works as a charm, regardless of window position on the screen or scrollbars position of the
Dim rpt As Point = PictureBoxPlan.PointToScreen(New Point(e.Location.X, e.Location.Y))
No need to take into account
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