Having checked the new v16 I was somewhat shocked to see that it is STILL not possible to adjust the style/thickness of trend/horizontal lines. I first mentioned this 4 years ago and I'm sure a lot of other people have as well.

It really can't be that difficult to implement as the option already exists on indicators and this is such a basic and necessary feature that even free charting software provides it.

I don't know if it will ever be possible. While the frequency of a particular suggestion seems to have an effect, I do not know why some suggestions get implemented right away while other suggestions take a long time to get implemented or don't get implemented at all.