[fix](trx-frontend-http): lift the header menus out of the header

Fixed positioning escaped the clipping, but not the stacking: the header
carries `z-index: 2`, which makes it a stacking context, so whatever
z-index a menu inside it carries is confined below level 2.  The spectrum
overlays paint as high as 9600, so both dropdowns opened underneath them.

Reparent each menu to the body when it opens.  Leaving that subtree is
the only way out of an ancestor's stacking context, and the menus are
already positioned in viewport coordinates, so nothing else about them
changes.  The outside-click test now considers the menu as well as its
wrapper, since the two are no longer nested.

Verified by hit testing rather than by inspecting z-index:
elementFromPoint at the open menu's centre returns the menu.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GdyUjuXejCEfiub675z6cz
Signed-off-by: Stan Grams <sjg@haxx.space>

src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/app.js

@@ -748,6 +748,25 @@ function elementById(id) {
     }
   }
   const overflowOrder = [".operator-layout-picker", ".header-style-pick", "#theme-toggle"];
+  function anchorMenu(button, menu) {
+    const rect = button.getBoundingClientRect();
+    if (menu.parentElement !== document.body) document.body.appendChild(menu);
+    menu.style.position = "fixed";
+    menu.style.zIndex = "9700";
+    menu.style.top = "0px";
+    menu.style.bottom = "auto";
+    menu.style.right = "auto";
+    const width = menu.offsetWidth || 200;
+    const height = menu.offsetHeight || 0;
+    menu.style.left = `${String(Math.round(Math.min(Math.max(8, rect.right - width), window.innerWidth - width - 8)))}px`;
+    const below = rect.bottom + 8;
+    if (below + height <= window.innerHeight - 8) {
+      menu.style.top = `${String(Math.round(below))}px`;
+    } else {
+      menu.style.top = "auto";
+      menu.style.bottom = `${String(Math.round(window.innerHeight - rect.top + 8))}px`;
+    }
+  }
   function installTopBarOverflow() {
     const actions = document.querySelector(".top-bar-actions");
     if (!actions || document.getElementById("top-bar-more")) return;
@@ -777,9 +796,14 @@ function elementById(id) {
     button.addEventListener("click", () => {
       const open = menu.classList.toggle("is-open");
       button.setAttribute("aria-expanded", String(open));
+      if (open) anchorMenu(button, menu);
     });
     document.addEventListener("click", (event) => {
-      if (!(event.target instanceof Node) || !wrap.contains(event.target)) closeMenu();
+      if (!(event.target instanceof Node)) {
+        closeMenu();
+        return;
+      }
+      if (!wrap.contains(event.target) && !menu.contains(event.target)) closeMenu();
     });
     document.addEventListener("keydown", (event) => {
       if (event.key === "Escape") closeMenu();
@@ -851,7 +875,10 @@ function elementById(id) {
     more.addEventListener("click", () => {
       const open = menu.classList.toggle("is-open");
       more.setAttribute("aria-expanded", String(open));
-      if (open) menu.querySelector('[role="menuitem"]')?.focus();
+      if (open) {
+        anchorMenu(more, menu);
+        menu.querySelector('[role="menuitem"]')?.focus();
+      }
     });
     document.addEventListener("click", (event) => {
       if (!(event.target instanceof Node) || !menu.contains(event.target) && !more.contains(event.target)) closeMore();

src/trx-client/trx-frontend/trx-frontend-http/assets/web/style.css

@@ -1531,25 +1531,10 @@ small { color: var(--text-muted); }
   align-items: center;
   gap: 0.2rem;
   min-width: 0;
-  /* Scroll rather than wrap: eight labels wrapped into a ragged block (four
-   * rows at 1100px) and made the header's height depend on the viewport. */
+  /* Never wraps and never scrolls: the occasional destinations live behind
+   * More, so four tabs plus More always fit.  overflow-x here would clip the
+   * dropdown this element anchors. */
   flex-wrap: nowrap;
-  overflow-x: auto;
-  scrollbar-width: thin;
-}
-/* Fade the trailing edge so a tab scrolled out of view reads as "there is more"
- * rather than as a label cut mid-word.  A mask rather than a colour-matched
- * cover gradient: the card is transparent, so a cover would have to track the
- * page background across both themes and all nine styles.  Only the trailing
- * edge is faded, so the first tab stays crisp when the strip is at rest. */
-.tab-bar-nav {
-  -webkit-mask-image: linear-gradient(to right, #000 calc(100% - 2rem), transparent 100%);
-  mask-image: linear-gradient(to right, #000 calc(100% - 2rem), transparent 100%);
-}
-.tab-bar-nav::-webkit-scrollbar { height: 3px; }
-.tab-bar-nav::-webkit-scrollbar-thumb {
-  border-radius: 3px;
-  background: color-mix(in srgb, var(--border-light) 70%, transparent);
 }
 .tab-bar-nav .tab { flex: 0 0 auto; }
 /* Icons before scrolling: every tab already carries one, and four icons plus

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/ui-core.ts

@@ -326,6 +326,39 @@ function elementById<T extends HTMLElement>(id: string): T {
   // Audio, record and the rig picker are the operating controls and stay.
   const overflowOrder = [".operator-layout-picker", ".header-style-pick", "#theme-toggle"];
 
+  // Anchored at paint time in fixed coordinates.  An absolutely positioned
+  // dropdown is clipped by any scrolling ancestor and trapped inside the
+  // stacking context its ancestors create, so it can end up squashed inside
+  // the bar or painted underneath page content.  Fixed positioning answers to
+  // the viewport instead, and the menu flips above its button near the bottom
+  // edge.
+  function anchorMenu(button: HTMLElement, menu: HTMLElement) {
+    const rect = button.getBoundingClientRect();
+    // Reparent to the body.  Fixed positioning escapes clipping but not
+    // stacking: the header sets `z-index: 2`, which makes it a stacking
+    // context, so any z-index the menu carries is confined below every panel
+    // that paints above level 2 — the spectrum overlays reach 9600.  Only
+    // leaving that subtree lets the menu sit above the page.
+    if (menu.parentElement !== document.body) document.body.appendChild(menu);
+    menu.style.position = "fixed";
+    menu.style.zIndex = "9700";
+    menu.style.top = "0px";
+    menu.style.bottom = "auto";
+    // The stylesheet pins these menus to the right of their anchor; leaving
+    // that in place while setting a left would stretch them across the bar.
+    menu.style.right = "auto";
+    const width = menu.offsetWidth || 200;
+    const height = menu.offsetHeight || 0;
+    menu.style.left = `${String(Math.round(Math.min(Math.max(8, rect.right - width), window.innerWidth - width - 8)))}px`;
+    const below = rect.bottom + 8;
+    if (below + height <= window.innerHeight - 8) {
+      menu.style.top = `${String(Math.round(below))}px`;
+    } else {
+      menu.style.top = "auto";
+      menu.style.bottom = `${String(Math.round(window.innerHeight - rect.top + 8))}px`;
+    }
+  }
+
   function installTopBarOverflow() {
     const actions = document.querySelector<HTMLElement>(".top-bar-actions");
     if (!actions || document.getElementById("top-bar-more")) return;
@@ -356,9 +389,11 @@ function elementById<T extends HTMLElement>(id: string): T {
     button.addEventListener("click", () => {
       const open = menu.classList.toggle("is-open");
       button.setAttribute("aria-expanded", String(open));
+      if (open) anchorMenu(button, menu);
     });
     document.addEventListener("click", (event) => {
-      if (!(event.target instanceof Node) || !wrap.contains(event.target)) closeMenu();
+      if (!(event.target instanceof Node)) { closeMenu(); return; }
+      if (!wrap.contains(event.target) && !menu.contains(event.target)) closeMenu();
     });
     document.addEventListener("keydown", (event) => { if (event.key === "Escape") closeMenu(); });
 
@@ -445,7 +480,10 @@ function elementById<T extends HTMLElement>(id: string): T {
     more.addEventListener("click", () => {
       const open = menu.classList.toggle("is-open");
       more.setAttribute("aria-expanded", String(open));
-      if (open) menu.querySelector<HTMLElement>('[role="menuitem"]')?.focus();
+      if (open) {
+        anchorMenu(more, menu);
+        menu.querySelector<HTMLElement>('[role="menuitem"]')?.focus();
+      }
     });
     document.addEventListener("click", (event) => {
       if (!(event.target instanceof Node) || (!menu.contains(event.target) && !more.contains(event.target))) closeMore();