Add dual colour option to an existing indicator main line.

Already discussed with coder.

• Add dual colour to the main line one for up and one for down
• Include up and down settings for colour choice
• The colour change needs to happen on each bar close/open, I've been informed by another coder that it requires a different line style or alternate way of making this happen as sometimes the colour change does not happen consistently which is important to the functionality.
• Not to use objects
• Extra buffers can be used but only one colour selector for up and down is preferred in settings.

I have added the first indicator that was made, but it has some errors occasionally in the colour change as shown in the jpg.