A short example: ```r library(ggplot2) p <- ggplot(economics_long, aes(date, value01, colour = variable)) + geom_line(size = .5) + guides(colour = guide_legend(override.aes = list(size = 2))) p ``` Notice the thicker lines in the legend on the right  However, this new element is ignored in ggplotly: ```r ggplotly(p) ```  This becomes even more critical when using a very low level of alpha, and then needing to adjust it for the legend. Thanks.