I think in one of the release posts I saw a technique to quickly "delete" a fillet, but I can't find it anymore. Do you know what I mean?

It was news of V5 beta ! ;) Third Video...

https://moi3d.com/forum/index.php?webtag=MOI&msg=11803.1

I recall having problems quite a while back in a job with fillets even though I rarely use them

I found that deleting/re-building the old surfaces that made up its edges (those edges before applying the fillet) made MOI a lot more responsive, as if it was now higher up the memory priority list in the program and this made it easier for the MOI software to deal with

Basically if it wouldn't do the fillet then I rebuilt that surface and then it worked fine

2 cents

[OT] The second video there just made my head explode!

Being able to move a circle around and after extrusion or boolean to remove is like parametric CAD that costs hundreds more!

Thanks Pilou! Will play around with that next. :)

For use the erase Fillet
there is a little trick of Selection! Use the Browser Faces / Planar then Shift + Red x (Bottom screen) or Shift+Del or Right Click !

Thanks Pilou for posting the planar trick!