I switched my AF setting to AF Lock ON and AF Lock Hold ON as I've always done since GH2 but now I have an external monitor.

It doesn't work with an external monitor connected: I'm in AFS and a single press of the AF Lock button should focuses the subject and lock the focus.

I press the button, I see AFL on the display but the camera doesn't focuses. I shut off the external monitor or I disconnect the hdmi cable and everything works again.

The strange thing is that the setting I normally use for macro (AF-Lock: AF-ON) works perfectly. I found several post on the net. It's not the cable and not the monitor. Do you know if a workaround exists? I have the latest fw.

P.S. I forgot to say I'm a underwater videographer, so the camera is inside an uw housing hence no magical Jedi tricks as touch screen AF or manual focus for WA shots.