onShowPreview() {
			const sReturnedURL = this._buildReturnedURL();
			const sURL = this._buildPreviewURL();

			if (!isValidUrl(sURL).result) {
				return;
			}
			const oIFrame = Element.getElementById("sapUiRtaAddIFrameDialog_PreviewFrame");
			// enable/disable expanding the Panel
			const oPanel = Element.getElementById("sapUiRtaAddIFrameDialog_PreviewLinkPanel");
			const oPanelButton = oPanel.getDependents()[0];
			if (sURL) {
				oPanelButton.setEnabled(true);
			} else {
				oPanel.setExpanded(false);
				oPanelButton.setEnabled(false);
			}
			try {
				this._oJSONModel.setProperty("/previousFrameUrl/value", sReturnedURL);
				this._oJSONModel.setProperty("/settingsUpdate/value", false);

				oIFrame.applySettings({ url: sURL, advancedSettings: {...this._oJSONModel.getProperty("/advancedSettings/value")} });
				// Use the URL from the IFrame to ensure that the complete path is shown
				this._oJSONModel.setProperty("/previewUrl/value", oIFrame.getUrl());
			} catch (oError) {
				Log.error("Error previewing the URL: ", oError);
			}
		}
Event handler for Show Preview button
@param {sap.ui.base.Event} oEvent - Event