unexpected results using ggplotly and geom_dotplot()

Hello! Thank you so much for your work on this great package.

I am having some trouble getting dot plots to work with plotly. For example, take a look at the following example from the documentation for geom_dotplot().

library(ggplot2)

p <- ggplot(mtcars, aes(x = factor(cyl), y = mpg)) +
  geom_dotplot(binaxis = "y", stackdir = "center")

p
#> `stat_bindot()` using `bins = 30`. Pick better value with `binwidth`.

Created on 2018-03-07 by the reprex package (v0.2.0).

When I then try to render this with plotly:

library(plotly)
ggplotly(p)

I get a blank plot.

I am getting lots of weird problems like this with my real data as well.

从 issue 中可复现的 R 示例开始，使用 ggplot2 的 geom_dotplot() 和 plotly 的 ggplotly() 比较源图与空白输出。当所提供的点图能够通过 ggplotly 正确渲染时，即视为完成；报告中不识别任何仓库文件或测试。