Square engine anyone?

I installed Freecad version 1.1 to see if I could get on with it. I have used Freecad a lot in the past but now mainly use Design spark or Solid edge.
I started to design a single cylinder simple IC engine. 25mm bore and stroke with some fillets to soften some of the edges. After drawing the cylinder I decided to section it by drawing a 26mm square on top of the cylinder and pocketing it through the cylinder to create a sectioned view. Several attempts later I realised Freecad still had problems with fillets, so I deleted them. I could then section the engine to examine the interior of the cylinder. I then pressed CTR Z to undo the section to restore the cylinder, deleted the now not needed drawing of the section square, and this happened. (see attached image).

Each time I tried to delete or alter the drawing of the square Freecad turned my round engine into a square one.

A square cylinder might just about work, but a square crankshaft? or a cam with square lobes?

There were engines with square cylinders, but square crankshaft would be tough to spin!  Reminds me of the square tire episode on Mythbusters. 

You just need one of those ball races with with a square hole hole in the inner race

If you are having to draw squares to get section views then it would seem Freecad is also rather lacking in the ability to section a single part let alone selectivly section parts in an assembly. I suppose you don't get what you don't pay for.