article focus / unfocus is still being tracked in the extension even after the article is closed

[mircealungu]

something's fishy there.
it's tracked even while on the words review page.
or on the exericses page.
from the activity data:

mysql> select time, event, article_id, extra_data from user_activity_data order by id desc limit 5;
+---------------------+---------------------------+------------+------------+
| time                | event                     | article_id | extra_data |
+---------------------+---------------------------+------------+------------+
| 2022-12-01 13:45:33 | ARTICLE LOST FOCUS        |    2117687 | EXTENSION  |
| 2022-12-01 13:45:30 | TO EXERCISES AFTER REVIEW |    2117687 | EXTENSION  |
| 2022-12-01 13:45:28 | ARTICLE FOCUSED           |    2117687 | EXTENSION  |
| 2022-12-01 13:43:24 | ARTICLE LOST FOCUS        |    2117687 | EXTENSION  |
| 2022-12-01 13:43:24 | ARTICLE FOCUSED           |    2117687 | EXTENSION  |
+---------------------+---------------------------+------------+------------+