avoid reordering axis categories when is a matrix; fixes #863

Author: cpsievert

NEWS.md

@@ -315,7 +315,7 @@ sorted alphabetically before scales are applied. Also, when mapping a factor to
 * Misspecified trace/layout attributes produce a warning.
 * New `plotly_data()` function for returning/inspecting data frame(s) associated with a plotly object.
 * New `plotly_json()` function for inspecting the data sent to plotly.js (as an R list or JSON).
-* `layout()` is now a generic function and uses method dispatch to avoid conflicts with `graphics:layout()` (fixes #464).
+* `layout()` is now a generic function and uses method dispatch to avoid conflicts with `graphics::layout()` (fixes #464).
 
 ## OTHER CHANGES:
 

R/utils.R

@@ -476,7 +476,9 @@ populate_categorical_axes <- function(p) {
     d <- lapply(p$x$data, "[[", axisType)
     isOnThisAxis <- function(tr) {
       is.null(tr[["geo"]]) && sub("axis", "", axisName) %in% 
-        (tr[[sub("[0-9]+", "", axisName)]] %||% axisType)
+        (tr[[sub("[0-9]+", "", axisName)]] %||% axisType) &&
+        # avoid reordering matrices (see #863)
+        !is.matrix(tr[["z"]])
     }
     d <- d[vapply(p$x$data, isOnThisAxis, logical(1))]
     if (length(d) == 0) next