Bafflng X VMware OsX issue


Never seen anything like this - what's happening please.

Vmware Fusion 3.something on mac running an Ubuntu 11.04 server but with X installed so clients can display on my mac. I clone the vm, change its hostname and use the VMware dhcpd.conf to give it a different IP address (I do this a lot for development - always worked fine up till now). So then I run the original and the cloned machine. On the clone I start firefox and on the original I also start firefox and amazed to find the firefoxes think they are only one instance. WHAT???????? They are running on different machines (only displaying on the same X server).

What on earth is going on here?

Thoughts :

NAT (each VM is "natted" is delivering to the wrong client)
Inter-client communication in X

If I save a file from each window both get saved to the same filesystem so definitely ff thinks there is only one instance running.

Totally baffled. Please help.

Doesn't seem to happen with other clients - tried kdiff3 for example - instances completely separate. Also, from each window I tried setting a bookmark and looking at history. History seems to be reflected in both. Bookmarks is reflected in both while both are running then one of them forgets that bookmark (both retain history).

Maybe this is some anti cross-site-scripting mechanism.

Just to make it clear - I'm running two separate FF clients on different machines displaying on the same X server and in my opinion that should behave like separate clients but they are in fact behaving as if there is only one client with several windows but common storage (except for bookmarks, which is almost like that).

My current thoughts are this is Firefox being clever discovering the other client and making them behave as one to avoid XSS issues. Its a pain as I often run several instances on different machines precisely *because* of the different context of each.