(contextMenuStrip2.SourceControl as Label).Text

ToolStripMenuItem it = (ToolStripMenuItem)sender;

        private void test2ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            MessageBox.Show(Convert.ToString((contextMenuStrip2.SourceControl as Label).Text));
        }

            ContextMenuStrip tsItem = (ContextMenuStrip)sender;
            ContextMenuStrip cMenuStrip = (ContextMenuStrip)tsItem.Owner;
            MessageBox.Show((cMenuStrip.SourceControl as Label).Text);

            // 
            // label1
            // 
            this.label1.ContextMenuStrip = this.contextMenuStrip2;
            // 
            // contextMenuStrip2
            // 
            this.contextMenuStrip2.Items.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.test1ToolStripMenuItem});
            this.contextMenuStrip2.Name = "contextMenuStrip2";
            this.contextMenuStrip2.Size = new System.Drawing.Size(153, 48);
            // 
            // test1ToolStripMenuItem
            // 
            this.test1ToolStripMenuItem.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.test2ToolStripMenuItem});
            this.test1ToolStripMenuItem.Name = "test1ToolStripMenuItem";
            this.test1ToolStripMenuItem.Size = new System.Drawing.Size(152, 22);
            this.test1ToolStripMenuItem.Text = "Test1";
            // 
            // test2ToolStripMenuItem
            // 
            this.test2ToolStripMenuItem.Name = "test2ToolStripMenuItem";
            this.test2ToolStripMenuItem.Size = new System.Drawing.Size(152, 22);
            this.test2ToolStripMenuItem.Text = "Test2";
            this.test2ToolStripMenuItem.Click += new System.EventHandler(this.test2ToolStripMenuItem_Click);

        Control rightClickedControl = null;
        private void test2ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            MessageBox.Show(rightClickedControl.Text);
        }

        private void contextMenuStrip2_Opening(object sender, CancelEventArgs e)
        {
            rightClickedControl = contextMenuStrip2.SourceControl;
        }

        private void test2ToolStripMenuItem1_Click(object sender, EventArgs e)
        {

        }

        private void test2ToolStripMenuItem1_Click(object sender, EventArgs e)
        {
            MessageBox.Show(Convert.ToString((sender as ToolStrip).Tag));
        }