First of all, thanks for your fast help on my subject Michael and Pilou. I played around a little bit more with the TRIM and EXTEND command. And, yes the TRIM command was a USER ERROR ... happens, unfortunately. As far as the EXTEND command goes, this seems to depend on the length of the segment I want to extend - attached is my test file, so you can try it yourself.

Since I din't have my setup from yesterday anymore, I tried to recreate the situation. There are four different versions. From LEFT to RIGHT, the first one works, the second doesn't, the third one doesn't work and the fourth one does. This was done in V2 Beta, haven't tried it in V1, asuming it will be the same behaviour. And I only created the version with the fillets because I thought it may have something to do with it, but obviously not. Anyways, this is just FYI.

Now, the TRIM command, knowing now what I have done wrong, I thought there are a whole bunch of clicks (7x) to achieve the desired result. So my thinking was, it would be nice ... and I don't know how hard this would be to implement - if I could just invoke the TRIM command and then click on the segment I want to remove and it would be gone (2 clicks). And in case there are two boundary segments ... clicking in between would remove the segment in between, so basically some automatic boundary recognition. I am familiar with this functionality from some other software, which I don't want to name here. Anyways, just a thought, would be nice. Despite all that, I think MOI rocks.

Armin