Disable hover effects when mouse leaves window.

control.go

@@ -39,6 +39,10 @@ func (b *ControlBase) Handle(ctx *Context, event sdl.Event) {
 		if b.IsMouseOver && e.Button == sdl.BUTTON_LEFT && e.Type == sdl.MOUSEBUTTONDOWN {
 			b.Invoke(ctx, b.OnLeftMouseButtonClick)
 		}
+	case *sdl.WindowEvent:
+		if e.Event == sdl.WINDOWEVENT_LEAVE {
+			b.IsMouseOver = false
+		}
 	}
 }
 

terrainrenderer.go

@@ -91,6 +91,11 @@ func (r *terrainRenderer) Handle(ctx *Context, event sdl.Event) {
 				r.project.update(ctx.Renderer)
 			}
 		}
+	case *sdl.WindowEvent:
+		if e.Event == sdl.WINDOWEVENT_LEAVE {
+			r.hover = nil
+			r.project.update(ctx.Renderer)
+		}
 	}
 }