You can go back into Slicex and zoom in on where you placed the markers. If you zoomed in far enough, you should see little circles and then the midline. Try to place the marker on a circle thats solid and on the midline. Do this to the starting marker and end marker of the loop. That should take care of the clicking and popping. If the sample is jumpy and you cant find a place where the circle is solid on the midline, drag the sample into Edison. Highlight a very small portion of the start of the sample and then click the uphill button, which is two steps from the "redo" button. This will make beginning start near to nothing. Then highlight a small portion of the end of the sample and click the downhill button, which is right below the uphill button. (FYI, you might have to click the uphill and downhill button a few times to see its affect) I hope this makes sense enough!