As explained near the end of https://ui.netbeans.org/docs/ui/code_folding/cf_uispec.html, the NetBeans IDE source code editor supports custom code folding tags for any language, like below (here defining the code folding tag in a Java comment, obviously need to use specific comment syntax for the respective language). // <editor-fold ...

Recently, to save myself sometime after having renamed some interfaces/classes in the ClipFlair project sourcecode, I right-clicked one of the class diagrams (.cd files) in it at Visual Studio’s “Solution Navigator” (this is an enhanced Solution Explorer addon) and using “Open With…” I opened up the diagrams with the XML editor to do a rename-all ...