Plotly - Changing dropdowns disables groupings for boxplot - r

Question

I'm creating a boxplot with dropdown options for the variable that gets plotted on the y axis. The data has 4 "people", and each observation has a type A or B. For each person 1:4, the chart plots bars for the observations A and B (example: https://plot.ly/r/box-plots/#grouped-box-plots).
I'm able to create it, but once I change the dropdown the groupings all get messed up. Here's example code:
library(plotly)
set.seed(123)
x <- rep(1:4, 6)
y1 <- rnorm(24, 5, 2)
y2 <- rnorm(24, 2, 5)
type <- rep(c("A", "A", "B", "B", "B", "B", "A", "A"), 3)
df <- data.frame(x, y1, y2, type)
p <- plot_ly(df, x = ~x) %>%
add_boxplot(y = ~y1, color = ~type, name = "First") %>%
add_boxplot(y = ~y2, color = ~type, name = "Second", visible = F) %>%
layout(
boxmode = "group",
title = "On/Off Box Plot",
xaxis = list(domain = c(0.1, 1)),
yaxis = list(title = "y"),
updatemenus = list(
list(
y = 0.8,
buttons = list(
list(method = "restyle",
args = list("visible", list(TRUE, FALSE)),
label = "y1"),
list(method = "restyle",
args = list("visible", list(FALSE, TRUE)),
label = "y2")))
)
)
p
The dropdown starts with y1 and looks exactly how I'd like, but changing the dropdown regroups the data and changing back to y1 doesn't get back to the original graph.
Here's what's happening to the groupings: After changing the dropdown, y1 groups all type "A" with y1 and y2 plotted next to each other. Option y2 does the same but uses type "B" data. I only want y1 data for both types A/B (like the original graph).
I'm guessing the ' boxmode = "group" ' line is getting lost during the switches, but I can't get it to work. Does anyone know how to maintain the groupings based on type? Thank you.

Answer 1

updatemenus should be length 4, because there are actually 4 traces (2 visible at a time). Note that for groups, each legend item has a corresponding trace. Unfortunately R's automatic repeating of vectors obscures this.
ie, the value for updatemenus should be:
updatemenus = list(
list(
y = 0.8,
buttons = list(
list(method = "restyle",
args = list("visible", list(TRUE, TRUE, FALSE, FALSE)),
label = "y1"),
list(method = "restyle",
args = list("visible", list(FALSE, FALSE, TRUE, TRUE)),
label = "y2")))
)