airport-editor: stop status flash from scrolling the map on vertex grab

Vertex drag auto-selects a surface; the select tip unhid a banner and
reflowed the layout under the cursor. Skip the tip while dragging and keep
the status strip always one line tall so messages never shove the map.

internal/web/static/css/openfsd/airport-editor.css

@@ -179,6 +179,25 @@
   border-radius: 2px;
 }
 
+/*
+ * Live editor status strip: always occupies one line of vertical space so
+ * show/hide never reflows the toolbar/map (vertex grab was scrolling the page).
+ * Empty state is invisible but still in normal flow.
+ */
+.apted-flash[data-js="status"] {
+  min-height: calc(1.25em + 0.7rem + 2px);
+  box-sizing: border-box;
+  margin: 0.25rem 0 0;
+  /* Avoid browser scrolling the flash into view on updates */
+  overflow-anchor: none;
+}
+.apted-flash[data-js="status"].is-empty {
+  visibility: hidden;
+  border-color: transparent;
+  background: transparent;
+  color: transparent;
+}
+
 .apted-flash-ok {
   background: #d1e7dd;
   color: var(--apted-ok);

internal/web/static/js/openfsd/airport-editor/main.js

@@ -111,7 +111,11 @@ function main() {
       if (doc.mode !== MODE_SELECT) return;
       doc.selection = normalizeSelection(sel);
       refresh();
-      syncSurfaceSelectTip();
+      // Vertex grab auto-selects the surface — do not flash a status banner
+      // (unhiding the flash strip reflows the page and scrolls the map).
+      if (!overlays.isVertexDragging()) {
+        syncSurfaceSelectTip();
+      }
     },
     onVertexDrag(si, vi, lat, lon) {
       setVertex(doc, si, vi, { lat, lon });
@@ -756,29 +760,31 @@ function main() {
   function showStatus(msg, isError) {
     const el = root.querySelector('[data-js="status"]');
     if (!el) return;
-    el.hidden = !msg;
+    // Keep the strip in layout always (never [hidden]) so messages do not
+    // expand the page and shove the map / scroll the viewport.
+    el.hidden = false;
     el.textContent = msg || '';
-    el.classList.toggle('apted-flash-err', !!isError);
+    el.classList.toggle('is-empty', !msg);
+    el.classList.toggle('apted-flash-err', !!isError && !!msg);
     el.classList.toggle('apted-flash-ok', !isError && !!msg);
-    el.setAttribute('role', isError ? 'alert' : 'status');
+    el.setAttribute('role', isError && msg ? 'alert' : 'status');
+    el.setAttribute('aria-hidden', msg ? 'false' : 'true');
   }
 
-  /** Status banner for surface select in Select mode (not mid-drag). */
+  /**
+   * Select tip lives in a reserved status strip (no layout jump). We no longer
+   * push a banner on every surface select — mode tip covers "drag vertices".
+   * Clear only our old tip text if present so deselect stays quiet.
+   */
   const SURFACE_SELECT_TIP =
     'Drag any white vertex to reshape. Click empty map to deselect.';
 
-  /**
-   * Show tip when selection is a surface; clear it when selection leaves a
-   * surface (empty-map deselect, aircraft select). Only on selection change.
-   */
   function syncSurfaceSelectTip() {
-    if (doc.mode === MODE_SELECT && doc.selection?.type === 'surface') {
-      showStatus(SURFACE_SELECT_TIP, false);
-      return;
-    }
-    // Drop only our tip — do not wipe errors or other status flashes.
     const el = root.querySelector('[data-js="status"]');
-    if (el && el.textContent === SURFACE_SELECT_TIP) {
+    if (!el) return;
+    // Quiet: do not inject tip on select (was causing scroll-on-grab).
+    // Clear stale tip if it is still showing from an older build/session.
+    if (el.textContent === SURFACE_SELECT_TIP) {
       showStatus('', false);
     }
   }

internal/web/static/js/openfsd/airport-editor/map-layers.js

@@ -788,6 +788,15 @@ export class OverlayController {
     this.vertexEditActive = !!active;
   }
 
+  /**
+   * True while a vertex pointer-drag is active (including the select that starts it).
+   * Callers use this to avoid layout-shifting status flashes mid-grab.
+   * @returns {boolean}
+   */
+  isVertexDragging() {
+    return !!(this._vertexDrag || this._dragging);
+  }
+
   /**
    * Draw preview polyline for in-progress draw session.
    * @param {{ lat: number, lon: number }[]} points

internal/web/templates/airport_editor.html

@@ -41,7 +41,8 @@
     <div class="apted-flash apted-flash-err" role="alert">{{ .FlashError }}</div>
     {{ end }}
 
-    <p class="apted-flash" data-js="status" hidden role="status"></p>
+    {{/* Always in flow (is-empty) so status text never reflows the map. */}}
+    <p class="apted-flash is-empty" data-js="status" role="status" aria-hidden="true"></p>
 
     <div class="apted-toolbar" role="toolbar" aria-label="Editor tools">
         <label class="btn btn-sm btn-outline-dark apted-file-btn">
@@ -212,7 +213,7 @@
   Static assets are go:embed into the openfsd binary — restart the process after
   JS/CSS changes. Query string busts browser cache when the binary is rebuilt.
 */}}
-<script src="/static/js/leaflet.js?v=vertex-edit-5"></script>
-<script src="/static/js/openfsd/leaflet.rotatedmarker.js?v=vertex-edit-5"></script>
-<script type="module" src="/static/js/openfsd/airport-editor/main.js?v=vertex-edit-5"></script>
+<script src="/static/js/leaflet.js?v=vertex-edit-6"></script>
+<script src="/static/js/openfsd/leaflet.rotatedmarker.js?v=vertex-edit-6"></script>
+<script type="module" src="/static/js/openfsd/airport-editor/main.js?v=vertex-edit-6"></script>
 {{ end }}