Hi, there's the "closeOnExternalClick" parameter you can set to "true" in the initialize function that prevent the mbExtruder to close clicking out on the page:

$("#extruderTop").buildMbExtruder({
                positionFixed:false,
                position:"top",
                width:350,
                extruderOpacity:1,
                autoCloseTime:0,
                closeOnExternalClick:true,
                autoOpenTime:1000,
                hidePanelsOnClose:false,
                onExtOpen:function(){},
                onExtContentLoad:function(){},
                onExtClose:function(){}
            });

I suggest you to download the 2.3 prerelease where I fixed several bugs:

https://github.com/pupunzi/jquery.mb.extruder/zipball/v.2.3