diff --git a/services/core/java/com/android/server/wm/AppWindowToken.java b/services/core/java/com/android/server/wm/AppWindowToken.java
index 42d6ec0..277a04b 100644
--- a/services/core/java/com/android/server/wm/AppWindowToken.java
+++ b/services/core/java/com/android/server/wm/AppWindowToken.java
@@ -367,6 +367,8 @@
         if (mClientHidden == hideClient || (hideClient && mDeferHidingClient)) {
             return;
         }
+        if (DEBUG_APP_TRANSITIONS) Slog.v(TAG_WM, "setClientHidden: " + this
+                + " clientHidden=" + hideClient + " Callers=" + Debug.getCallers(5));
         mClientHidden = hideClient;
         sendAppVisibilityToClients();
     }