diff --git a/lib/matplotlib/backends/qt4_editor/formlayout.py b/lib/matplotlib/backends/qt4_editor/formlayout.py
index e48a675d8e88..d599622e0bad 100644
--- a/lib/matplotlib/backends/qt4_editor/formlayout.py
+++ b/lib/matplotlib/backends/qt4_editor/formlayout.py
@@ -79,7 +79,7 @@ def choose_color(self):
     def get_color(self):
         return self._color
 
-    @QtCore.pyqtSignature("QColor")
+    @QtCore.Slot("QColor")
     def set_color(self, color):
         if color != self._color:
             self._color = color
@@ -88,7 +88,7 @@ def set_color(self, color):
             pixmap.fill(color)
             self.setIcon(QtGui.QIcon(pixmap))
 
-    color = QtCore.pyqtProperty("QColor", get_color, set_color)
+    color = QtCore.Property("QColor", get_color, set_color)
 
 def col2hex(color):
     """Convert matplotlib color to hex before passing to Qt"""
@@ -97,8 +97,7 @@ def col2hex(color):
 def to_qcolor(color):
     """Create a QColor from a matplotlib color"""
     qcolor = QtGui.QColor()
-    if isinstance(color, QtCore.QString):
-        color = str(color)
+    color = str(color)
     try:
         color = col2hex(color)
     except ValueError: