diff --git a/apps/vectorcraft/src/app.rs b/apps/vectorcraft/src/app.rs
index 288fa6cdc..0391b7534 100644
--- a/apps/vectorcraft/src/app.rs
+++ b/apps/vectorcraft/src/app.rs
@@ -35,7 +35,7 @@ impl eframe::App for App {
     // control channel asks for, and the frames carrying input it injected, to the automation roots
     // (`VectorcraftApp::with_automation_roots`), which are in force elsewhere in the process.
     fn logic(&mut self, ctx: &egui::Context, frame: &mut eframe::Frame) {
-        BEACON.enter(Stage::Logic);
+        let _timed = BEACON.enter_timed(Stage::Logic);
         file_access::unconfined(|| self.logic_frame(ctx, frame));
         self.app.finish_ime_logic(ctx);
         BEACON.enter(Stage::Idle);
@@ -43,7 +43,7 @@ impl eframe::App for App {
     /// Restore the borderless caption, apply platform menu and pen input, and hand the frame to the
     /// app's raw-input hook while the keyboard user is unconfined.
     fn raw_input_hook(&mut self, ctx: &egui::Context, raw: &mut egui::RawInput) {
-        BEACON.enter(Stage::Input);
+        let _timed = BEACON.enter_timed(Stage::Input);
         self.frame_start = Some(std::time::Instant::now());
         // winit gives the window its caption back when it changes the window's flags (maximize,
         // restore, …): take it off again before the frame is laid out (#1758).
@@ -68,7 +68,7 @@ impl eframe::App for App {
         BEACON.enter(Stage::Idle);
     }
     fn ui(&mut self, ui: &mut egui::Ui, frame: &mut eframe::Frame) {
-        BEACON.enter(Stage::Interface);
+        let _timed = BEACON.enter_timed(Stage::Interface);
         #[cfg(target_os = "macos")]
         {
             let bar = vectorcraft_ui_egui::chrome::APP_BAR_HEIGHT;
diff --git a/crates/ui-egui/src/hang_beacon.rs b/crates/ui-egui/src/hang_beacon.rs
index 3331a1e39..e47dbfc79 100644
--- a/crates/ui-egui/src/hang_beacon.rs
+++ b/crates/ui-egui/src/hang_beacon.rs
@@ -196,6 +196,14 @@ impl Beacon {
         self.bump();
     }
 
+    /// The interface thread enters `stage` of a frame, timed whatever the activity around it, so a
+    /// frame the system runs while a file dialog waits for the user is timed too. The activity
+    /// before it applies again when the guard is dropped.
+    pub fn enter_timed(&self, stage: Stage) -> ActivityGuard<'_> {
+        self.enter(stage);
+        self.activity(Activity::None)
+    }
+
     /// The interface thread starts `activity`; it ends when the guard is dropped, and the activity
     /// before it applies again.
     pub fn activity(&self, activity: Activity) -> ActivityGuard<'_> {
@@ -538,6 +546,20 @@ mod tests {
         assert!(B.take_input(), "the main window's input");
     }
 
+    #[test]
+    fn a_frame_run_while_a_dialog_waits_is_timed() {
+        let b = Beacon::new();
+        let _dialog = b.activity(Activity::Dialog);
+        assert!(!b.sample().busy(), "the dialog waits for the user");
+        {
+            let _timed = b.enter_timed(Stage::Interface);
+            assert!(b.sample().busy(), "a frame inside the dialog's wait");
+            b.enter(Stage::Drawing);
+        }
+        assert_eq!(b.sample().activity, Activity::Dialog, "the dialog again");
+        assert!(!b.sample().busy());
+    }
+
     #[test]
     fn a_window_shown_in_line_handed_to_the_system_is_marked() {
         static B: Beacon = Beacon::new();