Highlight Overlaps
The Highlight Overlaps 
tool finds
places where segments lie on top of one another — duplicated or overlapping lines and
arcs — and highlights the overlapping sections. Overlaps often occur when geometry is
imported or copied, and can cause a feature to be cut twice.
Finding and removing overlaps
Select the Highlight Overlaps tool. Any overlapping sections in the drawing are highlighted for inspection.
To remove them, hold Ctrl and click anywhere. Pix cleans up all overlapping polylines, removing the duplicated sections and stitching the remaining geometry back together.