Promiscuous vs monitor mode

Hi, It looks like my Wireshark is not running in monitor mode. This is in short. Now the extended version :-). I'm, running Wireshark 1.6.7 on Ubuntu 12.04. I activated monitor mode on mon0 interface through airmon. I set Wireshark to listen on mon0. When I open mon0 settings I can see that the "Capture packets in promiscuous mode" is enabled. "Capture packets in monitor mode" is not checked, and when I try to activate it I get error "The capabilities of the capture device "mon0" could not be obtained (That device doesn't support monitor mode)... Why is that so when airmon states that "monitor mode enabled on mon0"? When I'm sniffing on that interface i'm not getting any traffic from other machines within my wireless network. This indicates that nor the monitor mode nor the promiscuous mode is active on that interface (?). What am I doing wrong? This is my WLAN so I know the password (I set WPA2 Personal encryption on it). Thanks on any help.