I just realized (unfortunately after cutting out my muslin), that when I created the detail, I the center back seam on the front pants pattern piece and the center front seam on the back piece. I just need to reselect the correct curves and points on each piece. After checking the Seamly2D PDF Manual, it looked like the Add Node tool would do the trick. But when I clicked on one of the pieces in Detail and tried to use the tool, it won’t activate. How do I get it to load?
Never mind… I found it. In Draw mode, click Detail, then select the Insert Node Tool, then click on the item you want to add to pattern piece. A pop-up window lets you select which Detail (pattern) piece you want to add it to. Then go to the Details, right-click in the pattern piece, and select Options. That’s where you can edit nodes, add labels and seam allowances.