Here's how to proceed if you didn't write any custom change handlers, but only use the default change handlers provided by SAP.
If you only use default change handlers, register your change handlers directly in the library.js
file under extensions > flChangeHandlers
.
library.js
... extensions: { flChangeHandlers: { "sap.uxap.ObjectPageLayout": { "moveElements": "default" }, "sap.uxap.ObjectPageSection": { "hideControl": "default", "unhideControl": "default", "stashControl": "default", "unstashControl": "default" } } } ...