Add Articles – limited selection

Dear Stackideas team,
here is Mela from Kulmine.
Since two updates I have problems inserting a released article block into an article.
The selection of articles to choose from the menue is limited to about 15 articles or so. If I want to insert an articel that doesn't show up in this list, I use the search – but it's loading and loading and nothing happens.
Is there any workaround for this case, am I doing something wrong or will it be fixed with the next update?

Thanks in advance
Mela
for the Kulmine team


P.S.: if you need a screenshot or anything to clear up my question please ask.