conditional os in UI xml, add system dialog file open on osx, check api format or error message when opening a document, per-char text wrap on NodeText, additional info on create doc dialog like working path

src/node_dialog_open.cpp

@@ -232,6 +232,12 @@ void NodeDialogNewDoc::init_controls()
         if (btn_ok->on_click)
             btn_ok->on_click(btn_ok);
     };
+#if defined(_WIN32) || defined(__OSX__)
+    working_path = find<NodeText>("path");
+    static char path_buffer[256];
+    realpath(App::I.data_path.c_str(), path_buffer);
+    working_path->set_text_format("Working dir: %s", path_buffer);
+#endif
 }
 void NodeDialogNewDoc::loaded()
 {