Probably a lot of people already spotted this, but still: the notes don't make it super clear but the map editor now has an 'Experimental Features' dialog where you can disable all constraints on block placement (it's called 'Ghost Block' mode). It's basically block-mixing, built-in, without the need to mess around with external map editing programs.

Certainly makes it easier to visualise what mixed blocs will look like

YES

We had a good play around with it in the closed beta
Mr A did some nice block mix stuff

Please HELP...i can't find it, and Mpeditor unlimited doesn't work anymore.

In the editor click on the little "Hammer" in the bottom right corner next to the MediaTracker symbol. Then click on "Unlock Experimental Features" at the very bottom. Finally just check the boxes next to "Activate Air Mapping" and "Enable Mix Mapping"

and also hit f2 to get it to work

Yeah, really nice feature... I noticed that it can be useful to place terraform blocks first (without the blockmixing feature on) and THEN place the other blocks and mix with the terraform blocks, otherwise you will probably end up with graphical glitches and other ugly stuff.

Cool thanks buddy's. you make my day/week/month...let's