I don't know about that Window. I suspect you will have to model it and save it as a custom Window.
The main difference is when drawing a line chain (or rectangle). If you draw it with the Line Tool, each segment will be a single Line element. If you draw it with the Polyline Tool, the whole line chain will be one Polyline element. So if you need to move the line chain around the Polyline Tool is more convenient as you only need to select a single element.
Of course you could do the same with Line elements because if you create the line chain with the Line Tool, the Line segments will be automatically grouped so you will be able to move them as a single entity.
You can edit both a Polyline and a line chain made out of lines with Pet Palette commands like any other polygon type element geometry: you can add or remove nodes, curve edges, offset edges, etc.
The only difference is that in case of a line chain made up of Line elements, you need to have Grouping ON so you can select them as one element, then you need to turn Grouping OFF for the Pet Palette polygon editing commands to become available.
So in summary, I think the Polyline Tool is just more convenient then the Line Tool.
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