Core

please take a look into t3-trunk/typo3/js/modulemenu.js

There you have a function called loadModuleComponents.

This function basicly does the following:

1. check wether there are navigation components
 2. if yes show them
 3. load module

So far so good, but the following happens due to the behaviour of the navigation components:

1. check wether there are navigation components
 2. if yes show them
 3. load module
 4. after finishing navigation component load the contentArea is refreshed

So we have two loadings of the content area :(((

Solution:
- set contentArea to about:blank (or an extjs panel with always the same content (please select an element from the tree)
- change function, so that the loading only happens, if there is no navigation component ;)

<<<snipp
    TYPO3.Backend.NavigationIframe.getEl().parent().setStyle('overflow', 'hidden');
    } else {
        TYPO3.Backend.NavigationContainer.hide();
        TYPO3.Backend.NavigationDummy.show();
        --> do reload here only
        --> this.openInContentFrame(record.originalLink, params);
    }
    --> no reload here!
snap>>>

Regards
Kay

PS: Hopefully the declaration as bug is correct, could be also a feature (while i like to see that backported), or a task