plot_dendro renders with the graph all squashed to the right

when i run this code:

library(plotly)

set.seed(3)
N <- 50
df <- data.frame(x = rnorm(N), y = rnorm(N))
rownames(df) <- paste0("p_", 1:N) 

dend <- as.dendrogram(hclust(dist(df)))
plot_dendro(dend)

i end up with the dendrogram all squashed to the right:

Any idea how i can force it to fill in the entire graph viewer?

Run the supplied R example with plot_dendro(dend) and compare the resulting layout with the attached image. Start at the plot_dendro entry point and trace how the dendrogram dimensions are passed to the graph viewer; done means the rendered dendrogram fills the viewer instead of being squashed to the right.