controlling sub objects in poly lines

This is a closed polyline, how can I delete the edge? Is there some sub object selection mode for polylines?

This was the initial situation or problem, two control points lying on eachother, instead of dragging the edge and removing the extra polyline, is there a way to collapse or weld the overlapping elements?

either drag one on top of the other (sometimes they stick - don't know the rule) or use PEDIT and do similar thing following the steps

now i think about it i'd probably trim out the bit i didn't want (TRIM, enter, select polyline, enter, select segment) then fillet back together again. - if there were not hatches and other funny business involved.

with Acad 2010 if you put your cursor on top of the Grip you can Stretch, Add or Remove Vertex. Which may be what happened to create the unwanted segment in the first place.

as i've mentioned in another of your posts, it would help if you put what AutoCAD version you are using in your profile.

Place your cursor on the unwanted vertex and select "Remove Vertex".

I was beat to the punch.

Use the porperty palette it lets you step though each vertex and change the XY coordinates, or change the Closed property to NO, or pedit and edit vertex.