We've discussed this in the past:
http://www.gaiaflashframework.com/index.php/topic,2556.0.htmlBasically if you have lots of graphical assets in a higher depth swf (ex: the nav page) you'll probably have problems with mouse events being captured by the nav page, and not your current (middle depth) page. In order to avoid this, but still have a few items in the nav clickeable you need to set mouseEnabled = false to the TOP depth container, the NavPage loader, and the actual items you want not to capture mouse events. Usually you would expect to simply set mouseEnabled false to just those items (or the whole Nav).
The way to fix this is to have mouseEnabled set to false by default to all depth containers and swf loaders (page and assets).
Doing this does NOT prevent it's children to receive mouse events, unless you also set mouseChildren = false.
So, in a nutshell, doing this change does not break any current project, and saves the developer to start referencing depth containers and specially loaders to change it's mouseEnabled property if they can't get mouse events.
What do you think?