使用R的patchwork包布局绘图时图例未显示的问题

我尝试用patchwork的guide_area()和plot_layout(guides = "collect")来把共享图例放在指定的guide space中心位置，但图例却不见了。我期望图例出现在下图红色问号所在的位置（两个绘图区域上方的中心区域）。

library(ggplot2)
library(patchwork)

# 创建四个带共同图例的示例图，先隐藏各自图例
p1 <- ggplot(mtcars, aes(x = wt, y = mpg, color = factor(cyl))) + 
  geom_point() + 
  theme(legend.position = "none")

p2 <- ggplot(mtcars, aes(x = hp, y = mpg, color = factor(cyl))) + 
  geom_point() + 
  theme(legend.position = "none")

p3 <- ggplot(mtcars, aes(x = qsec, y = mpg, color = factor(cyl))) + 
  geom_point() +
  theme(legend.position = "none")

p4 <- ggplot(mtcars, aes(x = disp, y = mpg, color = factor(cyl))) + 
  geom_point() +
  theme(legend.position = "none")

# 定义布局模板
design2 <- 
"
ABC
DEE
"

# 组合绘图并设置布局
p1 + p2 + p3 + p4 + guide_area() +
  plot_layout(guides = "collect", widths = c(5, 5, 5), heights = c(5, 5), design = design2) 

内容的提问来源于stack exchange，提问作者Giuseppe Petri