guides = "collect" does not work when using different themes #466

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1. teunbrand commented on Mar 16, 2026

   

   teunbrand

   on Mar 16, 2026

   Collaborator

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   Hi Cédric,

   Patchwork merges guides that are identical on the grid level. It doesn't know about the ggplot2-level properties of guides (for example it doesn't know if they share breaks or glyphs or anything of the sort).

   To merge legends affected by different themes, you need to force them to use the same theme (or otherwise ensure they're styled identically).

   In the example below, we're forcing the first plot's legend to adapt to the same theme as the second plot.

   library(ggplot2)
   library(patchwork)
   
   p1 <- ggplot(mpg, aes(hwy, displ, color = drv)) +
     geom_point() +
     guides(color = guide_legend(theme = theme_minimal()))
   
   p2 <- ggplot(mpg, aes(cty, displ, color = drv)) +
     geom_point() + 
     theme_minimal()
   
   (p1 + p2) + plot_layout(guides = "collect") &
     theme(legend.position = "bottom")

   

   ^{Created on 2026-03-16 with reprex v2.1.1}

   👍React with 👍1Reacted by Cédric Scherer
2. z3tt commented on Mar 16, 2026

   

   z3tt

   on Mar 16, 2026

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   Nice example for the guide_legend() functionality! While preparing a "real-life" use case I also realized that one can use the same theme and then modify one plot as well.

   Closing this issue, but adding this example for the sake of completeness:

   library(ggplot2)
   library(patchwork)
   
   g1 <- ggplot(mpg, aes(hwy, displ, color = drv)) +
       geom_point() +
       theme_minimal()
   
   g2 <- ggplot(mpg, aes(drv, displ,  color = drv)) +
       geom_boxplot(color = "grey30") +
       geom_jitter(width = .1) + 
       theme_minimal()
   
   ## modify on the fly
   ((g1 + theme(panel.border = element_rect(color = "grey30", fill = NA))) + g2) + 
       plot_layout(guides = "collect") &
       theme(legend.position = "bottom")

   

   ## or change plot directly
   g1b <- ggplot(mpg, aes(hwy, displ, color = drv)) +
       geom_point() +
       theme_minimal() +
       theme(panel.border = element_rect(color = "grey30", fill = NA))
   
   (g1b + g2) + 
       plot_layout(guides = "collect") &
       theme(legend.position = "bottom")

   

   ^{Created on 2026-03-16 with reprex v2.1.1}
3. z3tt

   closed this as completedon Mar 16, 2026