To reproduce: please run the attached sample project and follow the steps from the gif file. Workaround: close the popup before showing the message or the dialog: private void radButtonElement1_Click(object sender, EventArgs e) { if (!radRibbonBar1.Expanded) { this.radRibbonBar1.RibbonBarElement.Popup.ClosePopup(Telerik.WinControls.UI.RadPopupCloseReason.Mouse); } RadMessageBox.Show("Test"); }