diff --git a/upsetplot/plotting.py b/upsetplot/plotting.py
index c69636b..8d859ab 100644
--- a/upsetplot/plotting.py
+++ b/upsetplot/plotting.py
@@ -532,7 +532,7 @@ def _plot_stacked_bars(self, ax, by, sum_over, colors, title):
         handles, labels = ax.get_legend_handles_labels()
         if self._horizontal:
             # Make legend order match visual stack order
-            ax.legend(reversed(handles), reversed(labels))
+            ax.legend(list(reversed(handles)), list(reversed(labels)))
         else:
             ax.legend()
 
@@ -792,10 +792,14 @@ def plot_matrix(self, ax):
                 }
             )
         )
-        styles["linewidth"].fillna(1, inplace=True)
-        styles["facecolor"].fillna(self._facecolor, inplace=True)
-        styles["edgecolor"].fillna(styles["facecolor"], inplace=True)
-        styles["linestyle"].fillna("solid", inplace=True)
+        styles.fillna({
+            "linewidth": 1,
+            "facecolor": self._facecolor,
+            "edgecolor": styles["facecolor"],
+            "linestyle": "solid"
+            }, 
+            inplace=True
+        )
         del styles["hatch"]  # not supported in matrix (currently)
 
         x = np.repeat(np.arange(len(data)), n_cats)
@@ -905,8 +909,8 @@ def make_args(val):
             for rect in rects:
                 width = rect.get_width() + rect.get_x()
                 ax.text(
-                    width + margin,
-                    rect.get_y() + rect.get_height() * 0.5,
+                    float(np.ravel(width + margin)[0]),
+                    float(np.ravel(rect.get_y() + rect.get_height() * 0.5)[0]),
                     fmt.format(*make_args(width)),
                     ha="left",
                     va="center",
@@ -916,8 +920,8 @@ def make_args(val):
             for rect in rects:
                 width = rect.get_width() + rect.get_x()
                 ax.text(
-                    width + margin,
-                    rect.get_y() + rect.get_height() * 0.5,
+                    float(np.ravel(width + margin)[0]),
+                    float(np.ravel(rect.get_y() + rect.get_height() * 0.5)[0]),
                     fmt.format(*make_args(width)),
                     ha="right",
                     va="center",
@@ -927,8 +931,8 @@ def make_args(val):
             for rect in rects:
                 height = rect.get_height() + rect.get_y()
                 ax.text(
-                    rect.get_x() + rect.get_width() * 0.5,
-                    height + margin,
+                    float(np.ravel(rect.get_x() + rect.get_width() * 0.5)[0]),
+                    float(np.ravel(height + margin)[0]),
                     fmt.format(*make_args(height)),
                     ha="center",
                     va="bottom",