diff --git a/nx/include/switch/services/applet.h b/nx/include/switch/services/applet.h
index ee02c6f0..2fc56b32 100644
--- a/nx/include/switch/services/applet.h
+++ b/nx/include/switch/services/applet.h
@@ -2468,6 +2468,10 @@ AppletOperationMode appletGetOperationMode(void);
 ApmPerformanceMode appletGetPerformanceMode(void);
 AppletFocusState appletGetFocusState(void);
 
+/**
+ * @brief Sets the current \ref AppletFocusHandlingMode.
+ * @note Should only be called with AppletType_Application.
+ */
 Result appletSetFocusHandlingMode(AppletFocusHandlingMode mode);
 
 ///@}
diff --git a/nx/source/services/applet.c b/nx/source/services/applet.c
index e66ac5ba..f83ed9f0 100644
--- a/nx/source/services/applet.c
+++ b/nx/source/services/applet.c
@@ -541,6 +541,8 @@ Result appletSetFocusHandlingMode(AppletFocusHandlingMode mode) {
     Result rc;
     bool invals[4];
 
+    if (__nx_applet_type != AppletType_Application)
+        return MAKERESULT(Module_Libnx, LibnxError_NotInitialized);
     if (mode >= AppletFocusHandlingMode_Max)
         return MAKERESULT(Module_Libnx, LibnxError_BadInput);