diff --git a/config/config.sample.php b/config/config.sample.php
index f4794aec4a8..d4450dae442 100644
--- a/config/config.sample.php
+++ b/config/config.sample.php
@@ -1349,7 +1349,8 @@ $CONFIG = [
 	 * By default, activities in team folders or external storages are only generated
 	 * for the current user. This is due to a limitations in current implementations.
 	 * This config flag makes activities in group folders and external storages work
-	 * like in normal shares (when set to ``true``).
+	 * like in normal shares (when set to ``true``). Setting this flag does not allow
+	 * past activities to be displayed (no retroactivity).
 	 *
 	 * WARNING: Enabling this comes with some CRITICAL trade-offs:
 	 *