Response: We can use “dygraphs” library in R and use functions within it named “dyHighlight” to highlight a particular series where the mouse is hovered on.  We take the lungDeaths sample dataset where there are multiple parameters with time-series data. We can use “dyHighlight” function to accomplish highlighting a particular series when selected as shown below. We can specify here a larger circle size for point highlighting as well as more decisively fade the non-highlighted series.  library(dygraphs) lungDeaths <- cbind(ldeaths, mdeaths, fdeaths) dygraph(lungDeaths, main = "Deaths from Lung Disease (UK)") %>%
dyHighlight(highlightCircleSize = 5,
highlightSeriesBackgroundAlpha = 0.2, hideOnMouseOut = FALSE)