Small presentation layers UI fixes

src/blenderbim/blenderbim/bim/module/layer/data.py

@@ -40,6 +40,8 @@ class LayersData:
 
     @classmethod
     def active_layers(cls):
+        if not bpy.context.active_object:
+            return []
         data = bpy.context.active_object.data
         if not data:
             return []

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

@@ -137,6 +137,7 @@ class RemovePresentationLayer(bpy.types.Operator):
 class AssignPresentationLayer(bpy.types.Operator):
     bl_idname = "bim.assign_presentation_layer"
     bl_label = "Assign Presentation Layer"
+    bl_description = "Assign presentation layer to the active representation of the active object"
     bl_options = {"REGISTER", "UNDO"}
     item: bpy.props.StringProperty()
     layer: bpy.props.IntProperty()
@@ -158,6 +159,7 @@ class AssignPresentationLayer(bpy.types.Operator):
 class UnassignPresentationLayer(bpy.types.Operator):
     bl_idname = "bim.unassign_presentation_layer"
     bl_label = "Unassign Presentation Layer"
+    bl_description = "Unassign presentation layer from the active representation of the active object"
     bl_options = {"REGISTER", "UNDO"}
     item: bpy.props.StringProperty()
     layer: bpy.props.IntProperty()