mobirise - Add block parameters to custom html block

So in mobirise 4.0.15 I have noticed that supplied template blocks have "block parameters" enabled, but custom html blocks do not.Looking at the source, I can see that the parameter properties which flow into sass are defined within <mbr-parameters>.However copy and pasting <mbr-parameters> into a custom html block does not enable "block parameters" for some reason.So how can I enable block parameters for a custom html block?...Read more