grid.arrange from gridExtras exiting with "only 'grobs' allowed in 'gList'" after update
<p>I just updated R, R Studio, and a bunch of packages including ggplot2 and gridExtras on my Mac. Now gridExtras is failing in basic plotting with the error:</p>

<p>"only 'grobs' allowed in "gList""</p>

<p>Here's some code that should work but does not:</p>

<pre><code>library(ggplot2)
p1 = qplot(1:10,rnorm(10))
p2 = qplot(1:10,rnorm(10))
library(gridExtra)
grid.arrange(p1, p2, ncol=2, main = "Main title")
</code></pre>

<p>This dumps out the following error:</p>

<pre><code>Error in gList(list(grobs = list(list(x = 0.5, y = 0.5, width = 1, height = 1,  : 
  only 'grobs' allowed in "gList"
In addition: Warning message:
In grob$wrapvp &lt;- vp : Coercing LHS to a list
</code></pre>

<p>Any help is appreciated!</p>