As suggested previously... If you wish to simply click on the sequence then it would very easy; i took it one step further and used some GDI+ so that you can draw a line joining the selection. You could make it easier using Web Browser & JS; many examples on GitHub..
You got further than me arnelgp; i just couldnt get my head around the code required in which i opted for JS instead but prefer not to use where possible . The mechanics are there; thanks for sharing this with us... Each time i look at your code i learn something new....