diff --git a/Design:-Palette-Management-UI.md b/Design:-Palette-Management-UI.md
index a7eb15f..6f9c7b7 100644
--- a/Design:-Palette-Management-UI.md
+++ b/Design:-Palette-Management-UI.md
@@ -52,3 +52,21 @@ How the user manages their palette. Three distinct views:
 ### Runtime handling
 
 Most pieces should already be in place. Need to review whether there should be a hook into storage to deal with add/remove nodes; so it could maintain a `package.json` file for the user.
+
+
+### Customising the catalog
+
+By default, the catalog will be one we provide. But it needs to be possible customise the list of catalogs it uses. This will be done via the existing `editorThemes` setting - https://github.com/node-red/node-red/wiki/Design%3A-Editor-Themes
+
+    editorTheme: {
+        ...
+        palette: {
+            catalogues: [ // An array of urls for catalogues
+                  "http://catalogue.nodered.org/catalogue.json",
+                  "..."
+            ],
+            categories: [] // <-- supersedes existing paletteCatagories option,
+            editable: true/false // Default: true. Allows the editable palette to be disabled entirely
+        }
+        ...
+    }