DOC-3243: Dialogs did not retain focus when using the block/unblock API. (#4018)

* Docs: DOC-3243 - Dialogs did not retain focus when using the block/unblock API.

* Update modules/ROOT/pages/8.4.0-release-notes.adoc

Co-authored-by: Mitchell Crompton <mitchell.crompton@tiny.cloud>

---------

Co-authored-by: Mitchell Crompton <mitchell.crompton@tiny.cloud>

Author: kemister85

modules/ROOT/pages/8.4.0-release-notes.adoc

@@ -300,6 +300,13 @@ In {productname} {release-version}, a check was added to prevent compression whe
 
 // CCFR here.
 
+=== Dialogs did not retain focus when using the block/unblock API.
+// #TINY-12918
+
+Previously, when a dialog was blocked (for example, while loading) and then unblocked, the loading spinner disappeared without automatically focusing any other element. As a result, focus escaped the editor entirely. When using an inline editor, this caused the dialog and the rest of the editor UI to disappear.
+
+In {productname} {release-version}, unblocking a dialog now focuses the first focusable element automatically, the same as when opening a dialog. This prevents the dialog and the rest of the editor UI from disappearing when using an inline editor.
+
 === Some formatting was not applied to items in multilevel list.
 // #TINY-13324