Added warning about arguments merge and replace

src/guides/v2.3/extension-dev-guide/build/di-xml-file.md

@@ -236,6 +236,11 @@ Node Format:
 </config>
 ```
 
+{:.bs-callout-warning}
+**Arguments on different stages**
+<br/>
+Configuration arguments are merged when they are declared on the same stage (Initial, Global, or Area-Specifc). If you declare new arguments on a higher stage, like Area-Specific, the arguments declared on the higher stage will replace the existing ones.
+
 {:.bs-callout-info}
 **Merging and Arguments**
 <br/>