The Network Configuration page fills in later fields (such as netmask, broadcast, etc.) based on earlier values. When the IP address 10.0.0.1 is entered, it fills in the netmask 255.255.0.0 which is a class B netmask. However, 10.x.x.x is a class A network; the correct mask should be 255.0.0.0.
Confirmed still broken in Winston Beta-2.
verified ... thanks for your report!
Fixed in latest internal version.
Confirmed; fixed in Winston Beta-3. Thanks!