Forms: a background form's highlight request applies at once

crates/engine/src/js.rs

@@ -194,6 +194,21 @@ impl Session {
         self.docs.iter_mut().find(|d| d.id == id).map(|d| std::mem::take(&mut d.js_output)).unwrap_or_default()
     }
 
+    /// The last field-highlight change (`app.runtimeHighlight`) scripts asked for in document
+    /// `id`, taken out of its waiting output; the rest stays for [`Session::take_js_output`].
+    pub fn take_js_highlight(&mut self, id: DocId) -> Option<bool> {
+        let doc = self.docs.iter_mut().find(|d| d.id == id)?;
+        let mut last = None;
+        doc.js_output.requests.retain(|r| match r {
+            Request::Highlight(on) => {
+                last = Some(*on);
+                false
+            }
+            _ => true,
+        });
+        last
+    }
+
     /// Run `script` in document `id`, for a button (`target`: the field, event "Mouse Up") or
     /// the console (no target). Field changes and `resetForm` are applied as one undoable step;
     /// everything else the script asked for is returned.

crates/ui-egui/src/js_ui.rs

@@ -67,14 +67,7 @@ impl PdfCraftApp {
                     &[("u", &u)],
                 ),
                 Request::SaveAs => self.run_command("file.save_as"),
-                // As the Highlight fields button does: this document and the next ones.
-                Request::Highlight(on) => {
-                    if let Some(i) = view {
-                        self.views[i].highlight_fields = on;
-                    }
-                    self.view_defaults.highlight_fields = on;
-                    self.session.set_field_highlight(on);
-                }
+                Request::Highlight(on) => self.script_highlight(id, on),
                 Request::Focus(_) | Request::Beep | Request::Reset(_) => {}
             }
         }
@@ -83,6 +76,16 @@ impl PdfCraftApp {
         }
     }
 
+    /// A form's script turned field highlighting on or off (`app.runtimeHighlight`): as the
+    /// Highlight fields button does, for document `id` and the next ones.
+    pub(crate) fn script_highlight(&mut self, id: DocId, on: bool) {
+        if let Some(v) = self.views.iter_mut().find(|v| v.id == id) {
+            v.highlight_fields = on;
+        }
+        self.view_defaults.highlight_fields = on;
+        self.session.set_field_highlight(on);
+    }
+
     /// Run a push button's JavaScript (its Mouse Up action).
     pub fn run_button_script(&mut self, id: DocId, field: &str, script: &str) {
         // A script reads the fields: include what's still being typed in one (#166).

crates/ui-egui/src/lib.rs

@@ -1380,6 +1380,9 @@ impl PdfCraftApp {
         if activate {
             let out = self.session.take_js_output(id);
             self.handle_js(id, out);
+        } else if let Some(on) = self.session.take_js_highlight(id) {
+            // The field highlight a form asks for isn't about the current document: now.
+            self.script_highlight(id, on);
         }
         Ok(id)
     }

crates/ui-egui/tests/pickers.rs

@@ -746,6 +746,22 @@ fn a_background_startup_forms_script_notice_waits_until_its_tab_is_selected() {
     assert!(h.state().toast.is_none(), "the notice is delivered once");
 }
 
+/// A form opened behind the current document that turns field highlighting on gets it at
+/// once, and so does the next document: only requests that act on the current document (a
+/// print, a save, a message) wait for its tab.
+#[test]
+fn a_background_forms_highlight_request_applies_at_once() {
+    let h = harness(&[3]);
+    assert!(!h.state().view_defaults.highlight_fields);
+    deliver_startup(&h, "late-form.pdf", pdfcraft_xfa::fixtures::shell(&pdfcraft_xfa::fixtures::layout_ready_template()));
+    let mut h = h;
+    h.run_steps(2);
+    assert_eq!(h.state().active, Some(0), "it opened behind the current document");
+    assert!(h.state().views[1].highlight_fields, "the background form is highlighted");
+    assert!(!h.state().views[0].highlight_fields, "the current document is left as it was");
+    assert!(h.state().view_defaults.highlight_fields, "the next document opens highlighted");
+}
+
 /// Embedded bytes and the PDF's original /UF name stay independent of the Save suggestion.
 fn attachment_fixture() -> Vec<u8> {
     attachment_pdf("invoice\u{202e}fdp.exe", b"hello notes")