原因：父窗体中ToolStripMenuItem默认的快捷键和系统快捷键冲突

解决方式：注释父窗体中默认的Ctrl+C和Ctrl+V快捷键

xxxDesigner.cs

//this.copyToolStripMenuItem.ShortcutKeys = ((System.Windows.Forms.Keys)((System.Windows.Forms.Keys.Control | System.Windows.Forms.Keys.C)));

 
//this.pasteToolStripMenuItem.ShortcutKeys = ((System.Windows.Forms.Keys)((System.Windows.Forms.Keys.Control | System.Windows.Forms.Keys.V)));