diff --git a/crates/ui-egui/src/dialogs/brush_options.rs b/crates/ui-egui/src/dialogs/brush_options.rs
index 3b3c16523..f03518b16 100644
--- a/crates/ui-egui/src/dialogs/brush_options.rs
+++ b/crates/ui-egui/src/dialogs/brush_options.rs
@@ -177,10 +177,20 @@ pub(super) fn open_new(app: &mut VectorcraftApp, ty: &str, ids: Option<Value>) -
     Ok(Value::Null)
 }
 
-/// OK of a new brush's Brush Options: `brush.new` with the type, the name, the values set and the
-/// dropped art's ids. The dialog closes once the brush is made.
+/// OK of a new brush's Brush Options: `brush.new` with the type, the name, the values set, the art
+/// the dialog opened with (`art` or `side` of `__def`, which the preview draws) and the dropped
+/// art's ids. A selection changed or cleared while the dialog is open does not change the art. The
+/// dialog closes once the brush is made.
 fn create(app: &mut VectorcraftApp, d: &Dialog) -> Result<Value, String> {
-    let mut p = json!({ "type": d.str("__type"), "name": d.str("name").trim(), "params": params(d) });
+    let mut brush_params = params(d);
+    if let Some(def) = d.fields.get("__def") {
+        for key in ["art", "side"] {
+            if let Some(art) = def.get(key).filter(|v| !v.is_null()) {
+                brush_params[key] = art.clone();
+            }
+        }
+    }
+    let mut p = json!({ "type": d.str("__type"), "name": d.str("name").trim(), "params": brush_params });
     if let Some(ids) = d.fields.get(IDS) {
         p["ids"] = ids.clone();
     }
diff --git a/crates/ui-egui/src/dialogs/new_brush.rs b/crates/ui-egui/src/dialogs/new_brush.rs
index 3746a5874..6ec926c07 100644
--- a/crates/ui-egui/src/dialogs/new_brush.rs
+++ b/crates/ui-egui/src/dialogs/new_brush.rs
@@ -166,6 +166,33 @@ mod tests {
         assert_eq!((&def["type"], &def["size"]), (&json!("calligraphic"), &json!(9.0)));
     }
 
+    /// The new brush takes the art its Brush Options opened with: changing or clearing the
+    /// selection while the dialog is open does not change the art, and OK still makes the brush.
+    #[test]
+    fn ok_makes_the_brush_from_the_art_the_dialog_opened_with() {
+        for (ty, key) in [("scatter", "art"), ("art", "art"), ("pattern", "side")] {
+            for change in ["select.set", "select.none"] {
+                let mut app = app();
+                app.run("shape.rectangle", json!({"x": 10, "y": 10, "width": 50, "height": 20})).unwrap();
+                app.run("ui.newBrush", json!({})).unwrap();
+                set(&mut app, json!({"type": ty}));
+                super::super::confirm(&mut app).unwrap();
+                let captured = app.ui.dialog.as_ref().unwrap().fields["__def"][key].clone();
+                assert!(captured.is_object(), "{ty}");
+                if change == "select.set" {
+                    app.run("shape.ellipse", json!({"x": 100, "y": 50, "width": 120, "height": 90})).unwrap();
+                } else {
+                    app.run("select.none", json!({})).unwrap();
+                }
+                super::super::confirm(&mut app).unwrap_or_else(|e| panic!("{ty} after {change}: {e}"));
+                assert!(app.ui.dialog.is_none(), "{ty} after {change}");
+                let name = format!("New {}{} Brush", ty[..1].to_uppercase(), &ty[1..]);
+                let def = app.run("brush.get", json!({ "name": name })).unwrap();
+                assert_eq!(def[key], captured, "{ty} after {change}");
+            }
+        }
+    }
+
     /// Cancel in New Brush, or in the Brush Options it opens, adds no brush and no undo step.
     #[test]
     fn cancel_adds_no_brush() {