private void mergeAttachmentToolStripMenuItem_Click(object sender, EventArgs e) { CloseAllChildForm(); MergeAttchmentFromSalesforce mergeAttachment = new MergeAttchmentFromSalesforce(); mergeAttachment.WindowState = FormWindowState.Maximized; mergeAttachment.MdiParent = this; mergeAttachment.MaximizeBox = false; mergeAttachment.MinimizeBox = false; mergeAttachment.Show(); }