https://learn.microsoft.com/zh-tw/dotnet/api/system.windows.forms.toolstripprofessionalrenderer.onrendertoolstripborder?view=netframework-4.8.1&redirectedfrom=MSDN
ToolStripProfessionalRenderer.OnRenderToolStripBorder Method (System.Windows.Forms) | Microsoft...
Raises the RenderToolStripBorder event.
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