Thanks, I'm glad you like it!

Yes, as you suspected with this type of geometry you often times can't just grab edges and move them around, except in special cases.

Here is one post that explains some of the reasons why: http://moi3d.com/forum/index.php?webtag=MOI&msg=170.25

There are actually some types of fancy (expensive) NURBS CAD systems that do let you perform some types of edits like you are showing there for stretching and moving faces around, but it actually requires a lot of calculations and specialized editing program code to do this, so this probably won't be in MoI anytime too soon.

Probably the easiest way to do that edit is to hack out a piece in the middle using Trim, and then move the pieces together and join them back together.

Another possibility that will leave you with a cleaner result but is a few more steps would be to to do Edit/Separate to blow that object apart into individual surfaces, then do a trim just of the longer side pieces (you can trim to a vertical line in that same view that you are showing), then move the rounded endpieces over to the new cut and join them back again, that will leave you without any extra edges like a simple slice out of the middle would do. If you want some more details on this method, please post your model and I will show you some steps.

In general often times you can do more "major surgery" on an object if you blow it apart into individual pieces with Edit/Separate, then edit the pieces and join later.

- Michael