意外注意到这个小细节: procedure TControl.WMLButtonUp(var Message: TWMLButtonUp); begin inherited; // 注意,如果是直接点击Form1,会执行TCustomForm.DefaultHandler(var Message);相当于给子类控件提供了新的处理消息的机会 if csCaptureMouse in ControlStyle then MouseCapture := False; if csClicked in C…
{ New TControlStyles: csNeedsBorderPaint and csParentBackground. These two ControlStyles are only applicable when Themes are Enabled in applications on Windows XP. csNeedsBorderPaint causes the ThemeServices to paint the border of a control with the…