preview external shading style as material is selected from other .blend file

previously it required to save external style attributes to preview the changes, now it's couple clicks saved if you want to preview different blender materials for your styles

src/blenderbim/blenderbim/bim/module/style/operator.py

@@ -316,6 +316,9 @@ class BrowseExternalStyle(bpy.types.Operator):
         attributes["Location"].string_value = filepath
         attributes["Identification"].string_value = f"{self.data_block_type}/{self.data_block}"
         attributes["Name"].string_value = self.data_block
+
+        style = tool.Ifc.get().by_id(self.active_surface_style_id)
+        bpy.ops.bim.activate_external_style(material_name=tool.Ifc.get_object(style).name)
         return {"FINISHED"}
 
 
@@ -331,9 +334,18 @@ class ActivateExternalStyle(bpy.types.Operator, tool.Ifc.Operator):
             material = context.active_object.active_material
         else:
             material = bpy.data.materials[self.material_name]
-        external_style = tool.Style.get_style_elements(material)["IfcExternallyDefinedSurfaceStyle"]
+
-        data_block_type, data_block = external_style.Identification.split("/")
+        props = context.scene.BIMStylesProperties
-        style_path = Path(tool.Ifc.resolve_uri(external_style.Location))
+        if props.is_editing:
+            location = props.external_style_attributes["Location"].string_value
+            identification = props.external_style_attributes["Identification"].string_value
+        else:
+            external_style = tool.Style.get_style_elements(material)["IfcExternallyDefinedSurfaceStyle"]
+            location = external_style.Location
+            identification = external_style.Identification
+
+        data_block_type, data_block = identification.split("/")
+        style_path = Path(tool.Ifc.resolve_uri(location))
 
         if style_path.suffix != ".blend":
             self.report(