Currently we only show the panel on the primary monitor, which means that additional monitors don't have any chrome on them. This gains us some space on the other monitors but at the price of having the app menu pretty much useless. 

This gets worse with increasing number of monitors assume a linear layout with 4 screens like this:

[P][_][_][A]

To open the app menu for app A you have to move the pointer over 3!! monitors. Even though most people don't use more than two monitors this example illustrates how broken this is.

Having the clock, usermenu etc on all monitors "by accident" when we do this wouldn't really hurt either as they would be easier to access.