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copied!<p>You could create a TTimer that polls the current mouse position every 0.10 seconds or so, then positions "AnotherComponent" according to the current mouse position.</p> <p>Then you wouldn't fire your event for every pixel of mouse movement- you won't need any OnMouseMove event on your controlling component at all.</p> <p>On my computer, this basically has no performance impact at all.</p> <pre><code>procedure TForm1.Timer1Timer(Sender: TObject); var pt: TPoint; begin //Is the cursor inside the controlling component? if so, position some //other control based on that mouse position. GetCursorPos(pt); if MouseWithin(pt.x,pt.y,MyComponent,Form1.Left,Form1.Top) then begin //replace with whatever real positioning logic you want AnotherComponent.Top := pt.y; AnotherComponent.Left := pt.x; end; end; function TForm1.MouseWithin(mouseX, mouseY: integer; const comp: TWinControl; const ParentWindowLeft: integer; const ParentWindowTop: integer): boolean; var absoluteCtrlX, absoluteCtrlY: integer; begin //take a control, and the current mouse position. //tell me whether the cursor is inside the control. //i could infer the parent window left & top by using ParentwindowHandle //but I'll just ask the caller to pass them in, instead. //get the absolute X & Y positions of the control on the screen //needed for easy comparison to mouse position, which will be absolute absoluteCtrlX := comp.Left + ParentWindowLeft; absoluteCtrlY := comp.Top + ParentWindowTop + GetSystemMetrics(SM_CYCAPTION); Result := (mouseX >= absoluteCtrlX) and (mouseX < absoluteCtrlX + comp.Width) and (mouseY >= absoluteCtrlY) and (mouseY <= absoluteCtrlY + comp.Height); end; </code></pre>

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