https://learn.microsoft.com/en-us/dotnet/api/system.windows.contentelement.onpreviewmousedown?view=windowsdesktop-10.0
ContentElement.OnPreviewMouseDown(MouseButtonEventArgs) Method (System.Windows) | Microsoft Learn
Invoked when an unhandled PreviewMouseDown attached routed event reaches an element in its route that is derived from this class. Implement this method to add...
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