Revert "Merge pull request #4347 from weseek/fix/backspace-in-vim"

This reverts commit 15b5d828d40346a3bc138752e559586067b4e856, reversing
changes made to 8d5d9ade3f8414bbe67f136e014146f369f97bb8.

packages/app/src/components/PageEditor/CodeMirrorEditor.jsx

@@ -900,7 +900,6 @@ export default class CodeMirrorEditor extends AbstractEditor {
 
         <ReactCodeMirror
           ref={(c) => { this.cm = c }}
-          detach
           className={additionalClasses}
           placeholder="search"
           editorDidMount={(editor) => {