[Ide] OptionsDialog checks for null panels.

Author: mkrueger

main/src/core/MonoDevelop.Ide/MonoDevelop.Ide.Gui.Dialogs/OptionsDialog.cs

@@ -663,6 +663,10 @@ SectionPage CreatePage (TreeIter it, OptionsDialogSection section, object dataOb
 						LoggingService.LogInternalError ("Error while creating options panel: " + node.Id, e);
 						continue;
 					}
+					if (panel == null) {
+						LoggingService.LogWarning ("Error panel == null: " + node.Id);
+						continue;
+					}
 					pi = new PanelInstance ();
 					pi.Panel = panel;
 					pi.Node = node;