diff --git a/src/Mod/Arch/ArchCommands.py b/src/Mod/Arch/ArchCommands.py
index e3de4dede4..858010f9b0 100644
--- a/src/Mod/Arch/ArchCommands.py
+++ b/src/Mod/Arch/ArchCommands.py
@@ -744,7 +744,7 @@ def pruneIncluded(objectslist,strict=False):
         if obj.isDerivedFrom("Part::Feature"):
             if not (Draft.getType(obj) in ["Window","Clone","Pipe","Rebar"]):
                 for parent in obj.InList:
-                    if parent.isDerivedFrom("Part::Feature") and not (Draft.getType(parent) in ["Facebinder","Window","Roof","Clone","Site"]):
+                    if parent.isDerivedFrom("Part::Feature") and not (Draft.getType(parent) in ["Space","Facebinder","Window","Roof","Clone","Site"]):
                         if not parent.isDerivedFrom("Part::Part2DObject"):
                             # don't consider 2D objects based on arch elements
                             if hasattr(parent,"Host") and (parent.Host == obj):
@@ -764,6 +764,8 @@ def pruneIncluded(objectslist,strict=False):
                             toplevel = True
         if toplevel:
             newlist.append(obj)
+        else:
+            FreeCAD.Console.PrintLog("pruning "+obj.Label+"n")
     return newlist
 
 def getAllChildren(objectlist):
diff --git a/src/Mod/Arch/ArchWall.py b/src/Mod/Arch/ArchWall.py
index 046703fd62..ab8847c5aa 100644
--- a/src/Mod/Arch/ArchWall.py
+++ b/src/Mod/Arch/ArchWall.py
@@ -804,6 +804,7 @@ class _Wall(ArchComponent.Component):
         if hasattr(obj,"Material"):
             if obj.Material:
                 if hasattr(obj.Material,"Materials"):
+                    # multimaterials
                     varwidth = 0
                     restwidth = width - sum(obj.Material.Thicknesses)
                     if restwidth > 0:
@@ -935,14 +936,15 @@ class _Wall(ArchComponent.Component):
                 offset = 0
                 base = []
                 for l in layers:
-                    l2 = length/2 or 0.5
-                    w1 = -totalwidth/2 + offset
-                    w2 = w1 + l
-                    v1 = Vector(-l2,w1,0)
-                    v2 = Vector(l2,w1,0)
-                    v3 = Vector(l2,w2,0)
-                    v4 = Vector(-l2,w2,0)
-                    base.append(Part.Face(Part.makePolygon([v1,v2,v3,v4,v1])))
+                    if l > 0:
+                        l2 = length/2 or 0.5
+                        w1 = -totalwidth/2 + offset
+                        w2 = w1 + l
+                        v1 = Vector(-l2,w1,0)
+                        v2 = Vector(l2,w1,0)
+                        v3 = Vector(l2,w2,0)
+                        v4 = Vector(-l2,w2,0)
+                        base.append(Part.Face(Part.makePolygon([v1,v2,v3,v4,v1])))
                     offset += l
             else:
                 l2 = length/2 or 0.5
diff --git a/src/Mod/Arch/ArchWindow.py b/src/Mod/Arch/ArchWindow.py
index fdb32fd157..cebb76d588 100644
--- a/src/Mod/Arch/ArchWindow.py
+++ b/src/Mod/Arch/ArchWindow.py
@@ -1881,6 +1881,8 @@ class _ArchWindowTaskPanel:
                     hinge = self.field6.property("text")
                     n = self.field7.currentIndex()
                     if (hinge.startswith("Edge")) and (n > 0):
+                        # remove accelerator added by Qt
+                        hinge = hinge.replace("&","")
                         t += "," + hinge + ",Mode" + str(n)
             ar.append(t)
 
diff --git a/src/Mod/Arch/importIFC.py b/src/Mod/Arch/importIFC.py
index 1d85dd052f..4b0ddda662 100644
--- a/src/Mod/Arch/importIFC.py
+++ b/src/Mod/Arch/importIFC.py
@@ -1534,7 +1534,7 @@ def export(exportList,filename,colors=None):
     # clean objects list of unwanted types
     objectslist = [obj for obj in objectslist if obj not in annotations]
     objectslist = Arch.pruneIncluded(objectslist,strict=True)
-    objectslist = [obj for obj in objectslist if Draft.getType(obj) not in ["Material","MaterialContainer","WorkingPlaneProxy"]]
+    objectslist = [obj for obj in objectslist if Draft.getType(obj) not in ["Dimension","Material","MaterialContainer","WorkingPlaneProxy"]]
     if FULL_PARAMETRIC:
         objectslist = Arch.getAllChildren(objectslist)
     products = {} # { Name: IfcEntity, ... }
@@ -2146,7 +2146,7 @@ def export(exportList,filename,colors=None):
                         treated.append(c.Name)
                 if subs:
                     ifcfile.createIfcRelAggregates(
-                        ifcopenshell.new(),
+                        ifcopenshell.guid.new(),
                         history,
                         'Assembly',
                         '',
@@ -2170,7 +2170,7 @@ def export(exportList,filename,colors=None):
             f = products[floor.Name]
             if children:
                 ifcfile.createIfcRelContainedInSpatialStructure(
-                    ifcopenshell.new(),
+                    ifcopenshell.guid.new(),
                     history,
                     'StoreyLink',
                     '',
diff --git a/src/Mod/Draft/DraftGui.py b/src/Mod/Draft/DraftGui.py
index a990b23334..3144d660de 100644
--- a/src/Mod/Draft/DraftGui.py
+++ b/src/Mod/Draft/DraftGui.py
@@ -262,6 +262,7 @@ def displayExternal(internValue,decimals=None,dim='Length',showUnit=True,unit=No
         uom = "??"
     if not showUnit:
         uom = ""
+    decimals = abs(decimals) # prevent negative values
     fmt = "{0:."+ str(decimals) + "f} "+ uom
     displayExt = fmt.format(float(internValue) / float(conversion))
     displayExt = displayExt.replace(".",QtCore.QLocale().decimalPoint())