[Arch] ArchMaterial 0.18 Fix Crash

As per discussion  https://forum.freecadweb.org/viewtopic.php?t=36806

src/Mod/Arch/ArchMaterial.py

@@ -259,14 +259,23 @@ def __init__(self,obj):
         obj.addProperty("App::PropertyPercent","Transparency","Arch",QT_TRANSLATE_NOOP("App::Property","The transparency value of this material"))
         obj.addProperty("App::PropertyColor","Color","Arch",QT_TRANSLATE_NOOP("App::Property","The color of this material"))
 
+    def isSameColor(self,c1,c2):
+
+        r = 4
+        if round(c1[0],r) == round(c2[0],r):
+            if round(c1[1],r) == round(c2[1],r):
+                if round(c1[2],r) == round(c2[2],r):
+                    return True
+        return False
+
     def onChanged(self,obj,prop):
 
         d = obj.Material
         if prop == "Material":
             if "DiffuseColor" in obj.Material:
                 c = tuple([float(f) for f in obj.Material['DiffuseColor'].strip("()").split(",")])
                 if hasattr(obj,"Color"):
-                    if obj.Color != c:
+                    if not self.isSameColor(obj.Color,c):
                         obj.Color = c
             if "Transparency" in obj.Material:
                 t = int(obj.Material['Transparency'])
@@ -296,11 +305,10 @@ def onChanged(self,obj,prop):
             d["Name"] = obj.Label
         elif prop == "Color":
             if hasattr(obj,"Color"):
-                val = str(obj.Color[:3])
                 if "DiffuseColor" in d:
-                    if d["DiffuseColor"] == val:
+                    if self.isSameColor(tuple([float(f) for f in d['DiffuseColor'].strip("()").split(",")]),obj.Color[:3]):
                         return
-                d["DiffuseColor"] = val
+                d["DiffuseColor"] = str(obj.Color[:3])
         elif prop == "Transparency":
             if hasattr(obj,"Transparency"):
                 val = str(obj.Transparency)
@@ -517,6 +525,11 @@ def accept(self):
         FreeCADGui.Control.closeDialog()
         FreeCAD.ActiveDocument.recompute()
 
+    def reject(self):
+        FreeCADGui.ActiveDocument.resetEdit()
+        FreeCADGui.Control.closeDialog()
+        FreeCAD.ActiveDocument.recompute()
+
     def chooseMat(self, card):
         "sets self.material from a card"
         if card in self.cards: