fix closestVisible

edit/sections-editor-section.js

@@ -94,6 +94,7 @@ function createSection({
   const cm = cmFactory.create(wrapper => {
     el.insertBefore(wrapper, $('.code-label', el).nextSibling);
   }, {value: originalSection.code});
+  el.CodeMirror = cm; // used by getAssociatedEditor
 
   const changeListeners = new Set();
 

edit/sections-editor.js

@@ -154,9 +154,7 @@ function createSectionsEditor({style, onTitleChanged}) {
   function closestVisible(nearbyElement) {
     const cm =
       nearbyElement instanceof CodeMirror ? nearbyElement :
-      nearbyElement instanceof Node &&
+        nearbyElement instanceof Node && getAssociatedEditor(nearbyElement) || getLastActivatedEditor();
-        (nearbyElement.closest('#sections > .section') || {}).CodeMirror ||
-      getLastActivatedEditor();
     if (nearbyElement instanceof Node && cm) {
       const {left, top} = nearbyElement.getBoundingClientRect();
       const bounds = cm.display.wrapper.getBoundingClientRect();
@@ -228,6 +226,15 @@ function createSectionsEditor({style, onTitleChanged}) {
     }
   }
 
+  function getAssociatedEditor(nearbyElement) {
+    for (let el = nearbyElement; el; el = el.parentElement) {
+      // added by createSection
+      if (el.CodeMirror) {
+        return el.CodeMirror;
+      }
+    }
+  }
+
   function getEditors() {
     return sections.filter(s => !s.isRemoved()).map(s => s.cm);
   }