Fix the / and [[ menus in live preview

The page's hidden text box also heard the live view's edits and showed its own menu in the wrong place, and the live line's menu was dropped when the view redrew. Only the box in use suggests now, the menu re-attaches when shown, and the caret lands inside a new code block.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

internal/web/static/editor.js

@@ -53,6 +53,7 @@ function makePopup(ta, wrap) {
     get open() { return !el.hidden; },
     show(list, pick, pos) {
       if (!list.length) return pop.hide();
+      if (el.parentNode !== wrap) wrap.append(el); // a redraw of the live view can drop it
       items = list; onPick = pick; sel = 0; draw(); el.hidden = false;
       const c = caretXY(ta, pos);
       el.style.left = Math.max(0, Math.min(ta.offsetLeft + c.x, wrap.clientWidth - 270)) + 'px';
@@ -79,7 +80,8 @@ function enhance(ta, wrap) {
   const pop = makePopup(ta, wrap);
 
   function check() {
-    if (ta.selectionStart !== ta.selectionEnd) return pop.hide();
+    // the page's own text box also hears the live view's edits (it holds the text); only the box in use may suggest
+    if (document.activeElement !== ta || ta.selectionStart !== ta.selectionEnd) return pop.hide();
     const pos = ta.selectionStart, ls = lineStart(ta.value, pos), before = ta.value.slice(ls, pos);
     let m;
     if ((m = /\[\[([^\[\]|\n]*)$/.exec(before))) {
@@ -93,7 +95,9 @@ function enhance(ta, wrap) {
       pop.show(SLASH.filter(c => !q || c.name.toLowerCase().includes(q) || c.keys.includes(q)), c => {
         const text = typeof c.text === 'function' ? c.text() : c.text;
         replaceRange(ta, from, pos, text);
-        if (c.caret) ta.setSelectionRange(from + c.caret, from + c.caret);
+        // in the live view a command that adds lines redraws it, and the box being typed in is a new one
+        const cur = ta.isConnected ? ta : wrap.querySelector('textarea.live-edit') || ta;
+        if (c.caret) cur.setSelectionRange(from + c.caret, from + c.caret);
         if (c.again) check();
       }, pos);
     } else pop.hide();