Trigger terms won't work in certain combinations

[gadget]

I've set up a trigger condition:

({Web.SRV.web4:net.tcp.service[ftp].last(0)}=0)

...which works.

Another trigger condition:

({Web.SRV.web4:icmpping.last(0)}=1)

...works fine too.

Now a combination of both these condition looks like this:

({Web.SRV.web4:net.tcp.service[ftp].last(0)}=0) & ({Web.SRV.web4:icmpping.last(0)}=1)

...and should become TRUE if the server is alive BUT httpd is down.

But the value never gets ON or OFF but is always UNKNOWN!

What am I doing wrong?

[Alexei]

WHen you add or change a trigger it becomes UNKNOWN. Then, it changes status to either ON or OFF if and only if new values for each trigger's item is received. Perhaps (for example) you have refresh rate set to 5 minutes for FTP check and you waited only 4 minutes?

[gadget]

Perhaps (for example) you have refresh rate set to 5 minutes for FTP check and you waited only 4 minutes?

No, every item I've set up has 30 seconds refresh time. It took me half an hour just to discover that these expressions never get a defined state, so that can't be the reason. Anyway, since I have set up depencencies I don't need this expression anymore. Nevertheless I think this might be a bug...