What version of vCloud Director are you using?
How are you creating an Edge without multi-interface support enabled? When I create a new Edge, there is no option for this, when I get done creating an Edge, the screen shows a green checkmark for multi-interface support.
The unchecked box you show in the screenshot appears briefly when I check the properties of any of my Edges and then disappears - I assume because the UI is checking the config, finding that is enabled, then hiding that checkbox option... I have tried with 1 and 2 external networks attached to the Edge and have the same results in each case.
Side Note for Christophe: There is not supposed to be a feature difference between compact vs. full mode, only performance diff
Message was edited by: Burke- --- After further reading here (http://pubs.vmware.com/vcd-51/index.jsp?topic=%2Fcom.vmware.vcloud.install.doc_51%2FGUID-942EDFB8-6699-4DDB-A0C0-25761AD9AB6C.html ) it seems this may present itself when you have upgraded edges - is this the case for your environment??