problem with generating overlay is shown as a message to the user

frontend-js/src/main/js/gui/leftPanel/OverlayPanel.js

@@ -161,9 +161,9 @@ OverlayPanel.prototype.createOverlayRow = function(overlay, checked) {
     checkbox.checked = checked;
     checkbox.onclick = function() {
       if (this.checked) {
-        return self.getMap().openDataOverlay(overlay.getId());
+        return self.getMap().openDataOverlay(overlay.getId()).then(null, GuiConnector.alert);
       } else {
-        return self.getMap().removeSelectedLayout(overlay.getId());
+        return self.getMap().removeSelectedLayout(overlay.getId()).then(null, GuiConnector.alert);
       }
     };
     viewTd.appendChild(checkbox);