I used a very similiar script but it didn't worked well. Did you used yours excessively? In my case (with my own script) sometimes the stitch dialog callback was noticed but the script-click to the button wasn't made. I don't know why. Maybe sometimes the window is to slow and the press-message is sent too fast. But…
* Convert a UV vertex selection to a Geometry vertex selection * The resulted Geo vertex select and now convert to UV selected verts * substract your inital edge to vertex UV selection you should have the counter vertex selection in UV space which you can convert back to an edge selection. In TexTools (open mzp with ZIP…