I would like to have the format of a trenline to be different from the actual line. For example the line is in green and the trendline should be dotted in red
My understanding is, if you have selected one of the Trendlines against your expression then it will be the same colour as the expression (you cannot make it different).
In order to have a different colour you will need to create a separate expression that you will use as your Trendline.
