diff --git a/python/jupytercad_core/src/stlplugin/model.ts b/python/jupytercad_core/src/stlplugin/model.ts
index 4e495956..9b1c9322 100644
--- a/python/jupytercad_core/src/stlplugin/model.ts
+++ b/python/jupytercad_core/src/stlplugin/model.ts
@@ -17,6 +17,10 @@ export class JupyterCadStlDoc extends JupyterCadDoc {
     this._source.observeDeep(this._sourceObserver);
   }
 
+  setSource(value: string) {
+    this._source.insert(0, value);
+  }
+
   get version(): string {
     return '0.1.0';
   }
diff --git a/python/jupytercad_core/src/stlplugin/modelfactory.ts b/python/jupytercad_core/src/stlplugin/modelfactory.ts
index 94756fbd..339b70e7 100644
--- a/python/jupytercad_core/src/stlplugin/modelfactory.ts
+++ b/python/jupytercad_core/src/stlplugin/modelfactory.ts
@@ -1,10 +1,11 @@
 import { IJupyterCadDoc, JupyterCadModel } from '@jupytercad/schema';
 import { DocumentRegistry } from '@jupyterlab/docregistry';
 import { Contents } from '@jupyterlab/services';
+import { JupyterCadStlDoc } from './model';
 
 class JupyterCadSTLModel extends JupyterCadModel {
   fromString(data: string): void {
-    this.sharedModel.source = data;
+    (this.sharedModel as JupyterCadStlDoc).setSource(data);
     this.dirty = true;
   }
 }