Bridge and tap device troubles

[manmach <networkmanager-list humanemachines nl>]

Hi,

I am new at this so I might be asking a silly question, but I have not 
been able to find an answer on the list or anywhere else on the web.

For VirtualBox bridged networking I have created a bridge (br0) and 
added my network interface (eth0) and the tap device (tap0) for my 
virtual machines to it.

Both tap0 and eth0 have been set to manual, both with IP 0.0.0.0 but 
eth0 in promisc mode. br0 is set to automatically acquire an IP via DHCP 
and to bridge eth0 and tap0.

When I boot my system, all is as expected. The interfaces all come up 
and I can connect to the virtual machine and the virtual machine can 
connect to the rest of the network, including the internet.

Before this, I had only eth0 set to DHCP and when I disconnected the 
network cable, the applet icon would indicate there was no connection. 
And once I reconnected the cable the icon changed into an animation for 
a while and then indicate a connection again.

But after the bridge has been created, the icon does not change anymore. 
Whether there is a connection or not, it will always indicate there is one.

Am I experiencing a lack of capability to handle the situation, have I 
run into a bug, or have I done something wrong?

regards,
Erik