The menubar root item doesnot open its content until there is another action invoked on the same page. Example - If I open a combobox present near the menubar and then click on the root item, the root item shows the content else it doesnot respond to click function.
I tested this on 7.2.2 and it seems to work fine. What version are you using? are you using a custom widgetset? any listeners or commands in the menu? And lastly, are there any javascript exeptions when this happens?
Sorry about all the questions, but they will help narrow things down.
Jun 25, 2014 2:15:05 PM com.vaadin.server.communication.ServerRpcHandler parseInvocation
WARNING: RPC call to v.v received for connector 4970 but no such connector could be found. Resynchronizing client.
Using custom widgetset - basically only for addons
No commands/listeners
No javascript exceptions
Actually after complete UI is shown, the click event on menubar root doesnot work.
Then after clicking on other components, the above warning message is shown(WARNING: RPC call to v.v received for connector 4970 but no such connector could be found. Resynchronizing client.)
The second issue comes from the fact that you are accessing a Vaadin UI from an outside thread (not the request thread). All such calls need to go through UI.access(); you need to wrap the accessing code inside a Runnable.
The first issue isn’t an issue in most cases; I’m not sure it has anything to do with your case. Fix the one above first and look for other issues after that.
I had this issue once, with the same first error as you (Could not determine…) when I had a MenuBar in a CssLayout. When I changed the CssLayout to a HorizontalLayout, the items in the menu did show up.