BrowserPlugin: the folder observer sets the document model instead of the folder model on an event

The BrowserPlugin has two Model observers, one for documents and one for folders. When these receive an event they pass their model on to the setModel method of the BrowserPlugin, making it available for other plugins through the wicket.model property.

The problem here is that the folder observer passes the document model to the BrowserPlugin, where it should pass the folder model.