Windows 7 Professional 64-bit on a laptop here.
I have 2 adapters - LAN and WLAN. If LAN only is enabled, then it'll get an IP address just fine. If I disable LAN and enable WLAN, that will also get an IP address (the same one; the DHCP server is configured to give it to both MAC addresses). LAN hardware identifies as "Broadcom NetLink (TM) Gigabit Ethernet", WLAN as "Intel(R) WiFi Link 5100 AGN".
However, if I unplug the LAN without enabling it and enable the LAN, the WLAN is not accepting the IP address that it is offered (I can see the DHCP server continually offering the correct address; Windows 7 does not accept it). If I then disable the disconnected LAN connection the WLAN connection will finally accept the address it is being offered.
How can I change this behaviour so that the WLAN will accept an address as soon as it is offered? When moving a laptop away from a desk I don't want to fiddle with"Control Panel\All Control Panel Items\Network Connections" every time.
If I tell the DHCP server to assign a different address to the LAN and WLAN MAC addresses the problem doesn't occur, although that's not a practical workaround since I can no longer predict what IP address I'll be assigned at any one time.