Re: How to make only selected line chart diff color from other ?
The way you had the highlighted line showing would only work if there was only one selected COMPETITOR. You can approach this using Set Analysis and have any possible dimension values highlighted with all the others transparent.
In your example the Set Analysis around year was causing confusion, so I took it out, similarly with the Dimension Limits.
This then gives a chart like this when two values are selected:
What is going on here is the COMPETITOR= in the expression is causing the selection on the Competitors to be ignored - hence all lines show all the time. In the colour expression we are doing the same expression in the if, but without the set analysis sum(REVENUE_C) > 0 , so only when the calculation without set analysis gives a result do we colour the line green, otherwise we go for a highly transparent black line - giving the result you see.
Because you had two outliers in your data it made the chart work less well (so I removed them), also the fact that not all competitors exist across all ten years it doesn't work quite so good.
Hopefully it illustrates how to achieve what Arturo Muñoz was showing in his blog post though.