diff --git a/notes.md b/notes.md
index 2e3c6819..de8971e6 100644
--- a/notes.md
+++ b/notes.md
@@ -17,6 +17,7 @@
 
 * `B` fix adaptive slicing with multi-extruder
 * `B` fix supports with grouped parts
+* `F` speculative background preview generation
 * `F` control for size of purge block (with 0=disabled)
 * `F` add separate fill speed control
 * `F` manual support addition / control
@@ -46,6 +47,7 @@
 * `B` fails in pancaking (clone) when there are no sliced layers (like z bottom too high)
 * `B` contouring should extend beyond part boundaries by tool radius
 * `B` outside cutting direction in roughing mode inverted
+* `B` widen outside cuts to prevent chatter on deep (metal) features
 * `F` z bounded slices (extension of z bottom offset feature)
 * `F` use arcs to connect hard angles
 * `F` lead-in milling
diff --git a/src/kiri/main.js b/src/kiri/main.js
index 4f45aef5..31577a9c 100644
--- a/src/kiri/main.js
+++ b/src/kiri/main.js
@@ -1140,16 +1140,19 @@
         } else {
             ajax(url, function(vertices) {
                 vertices = js2o(vertices).toFloat32();
-                platform.add(newWidget().loadVertices(vertices));
-                if (onload) onload(vertices);
+                let widget = newWidget().loadVertices(vertices);
+                platform.add(widget);
+                if (onload) onload(vertices, widget);
             });
         }
     }
 
     function platformLoadSTL(url, onload) {
-        new MOTO.STL().load(url, function(vertices) {
-            platform.add(newWidget().loadVertices(vertices));
-            if (onload) onload(vertices);
+        new MOTO.STL().load(url, function(vertices, filename) {
+            let widget = newWidget().loadVertices(vertices);
+            widget.filename = filename;
+            platform.add(widget);
+            if (onload) onload(vertices, widget);
         })
     }
 
diff --git a/src/kiri/widget.js b/src/kiri/widget.js
index 4faeb85c..499fc42e 100644
--- a/src/kiri/widget.js
+++ b/src/kiri/widget.js
@@ -295,6 +295,7 @@
     PRO.saveToCatalog = function(filename) {
         let widget = this;
         let time = UTIL.time();
+        widget.filename = filename;
         KIRI.catalog.putFile(filename, this.getGeoVertices(), function(vertices) {
             if (vertices && vertices.length) {
                 console.log("saving decimated mesh ["+vertices.length+"] time ["+(UTIL.time()-time)+"]");
diff --git a/src/moto/load-stl.js b/src/moto/load-stl.js
index 49fe09bf..c12dfc9b 100644
--- a/src/moto/load-stl.js
+++ b/src/moto/load-stl.js
@@ -32,7 +32,15 @@
         function onloaded (event)  {
             if (event.target.status === 200 || event.target.status === 0)  {
                 stl.parse(event.target.response || event.target.responseText);
-                if (callback) callback(stl.vertices);
+                let cd = xhr.getResponseHeader('Content-Disposition');
+                if (cd) {
+                    cd = cd.split(';').map(v => v.trim()).filter(v => {
+                        return v.indexOf('filename=') === 0;
+                    }).map(v => {
+                        return v.substring(10,v.length-1);
+                    });
+                }
+                if (callback) callback(stl.vertices, cd ? cd[0] : undefined);
             } else {
                 if (callback) callback(null, event.target.statusText);
             }