diff --git a/package.json b/package.json
index 80af535..4693fe0 100644
--- a/package.json
+++ b/package.json
@@ -50,6 +50,7 @@
   "dependencies": {
     "@types/react": "^16.14.5",
     "@types/react-dom": "^16.9.12",
+    "prop-types": "^15.5.7",
     "react": "^17.0.2",
     "react-dom": "^17.0.2",
     "react-sortable-hoc": "^2.0.0"