adds option for different selection modes

src/panels/panel.py

@@ -13,4 +13,19 @@ class BakeToIDMapPanel(bpy.types.Panel):
         layout.use_property_split = True
         layout.use_property_decorate = False  # No animation.
 
-        self.layout.operator("object.bake_to_id_map", text="Bake")
+        props = context.scene.bake_to_id_props
+
+        operator_row = layout.row()
+        operator_row.operator("object.bake_to_id_map", text="Bake")
+        operator_row.enabled = self.check_if_props_valid(context, props)
+
+        layout.prop(props, "selection_mode")
+
+    def check_if_props_valid(self, context, props):
+        if (props.selection_mode == "SINGLE" and context.active_object is None):
+            return False
+
+        if (props.selection_mode != "SINGLE" and len(context.selected_objects) < 1):
+            return False
+
+        return True