diff --git a/changelog.md b/changelog.md
index feab47f..2788079 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## [1.7.0] - 2024-12-14
+
+- Add `data-compartment` attribute to SVG output for identifying the compartment index when building interactivity.
+
 ## [1.6.3] - 2024-12-01
 
 - Fix bug when running `nomnoml-cli` with input files in the same directory.
diff --git a/dist/nomnoml.js b/dist/nomnoml.js
index e25c808..a35a916 100644
--- a/dist/nomnoml.js
+++ b/dist/nomnoml.js
@@ -1144,6 +1144,7 @@
             const style = config.styles[node.type] || styles.class;
             g.save();
             g.setData('name', node.id);
+            g.setData('compartment', undefined);
             g.save();
             g.fillStyle(style.fill || config.fill[level] || last(config.fill));
             g.strokeStyle(style.stroke || config.stroke);
@@ -1157,12 +1158,15 @@
                 g.path(divider.map((e) => add(e, { x, y }))).stroke();
             }
             g.restore();
+            let partIndex = 0;
             for (let part of node.parts) {
                 const textStyle = part === node.parts[0] ? style.title : style.body;
                 g.save();
+                g.setData('compartment', String(partIndex));
                 g.translate(x + part.x, y + part.y);
                 g.setFont(config.font, config.fontSize, textStyle.bold ? 'bold' : 'normal', textStyle.italic ? 'italic' : 'normal');
                 renderCompartment(part, style.stroke, textStyle, level + 1);
+                partIndex++;
                 g.restore();
             }
             g.restore();
@@ -1440,7 +1444,7 @@
                 return this.parent;
             }
             serialize() {
-                const data = getDefined(this.group(), (e) => e.data) ?? {};
+                const data = getAncestorData(this.group()) ?? {};
                 const attrs = toAttrString({ ...this.attr, ...data });
                 const content = this.children.map((o) => o.serialize()).join('\n');
                 if (this.text && this.children.length === 0)
@@ -1453,6 +1457,11 @@
 </${this.name}>`;
             }
         }
+        function getAncestorData(group) {
+            if (!group)
+                return syntheticRoot.data;
+            return { ...getAncestorData(group.parent), ...group.data };
+        }
         function getDefined(group, getter) {
             if (!group)
                 return getter(syntheticRoot);
@@ -1744,7 +1753,7 @@
         return processImports(loadFile(rootFileName), loadFile, maxImportDepth);
     }
 
-    const version = '1.6.3';
+    const version = '1.7.0';
 
     exports.ImportDepthError = ImportDepthError;
     exports.ParseError = ParseError;
diff --git a/package-lock.json b/package-lock.json
index a4a735a..40a5224 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "nomnoml",
-  "version": "1.6.3",
+  "version": "1.7.0",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "nomnoml",
-      "version": "1.6.3",
+      "version": "1.7.0",
       "license": "MIT",
       "dependencies": {
         "graphre": "^0.1.3"
diff --git a/package.json b/package.json
index e6b217c..64bf19d 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "nomnoml",
-  "version": "1.6.3",
+  "version": "1.7.0",
   "description": "The sassy UML renderer that generates diagrams from text",
   "homepage": "http://www.nomnoml.com",
   "author": "Daniel Kallin <daniel.kallin@gmail.com>",
diff --git a/src/index.ts b/src/index.ts
index c50b82c..27be35b 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -6,7 +6,7 @@ export {
   processAsyncImports,
   ImportDepthError,
 } from './nomnoml'
-export const version = '1.6.3'
+export const version = '1.7.0'
 
 export * as skanaar from './util'
 export { parse, ParseError } from './parser'