One page has been moved in the page tree structure. It was a second level child, now it is a third level child. The change has been made in the default language - English. Before this change the page had already been translated to other languages. After the change I noticed that the translated versions don't appear in the tree, neither in the old place nor in the new one.
In the database table Composite_Data_Types_IPageStructure seems to define child-parent relations, not depending on the language at all (all pages have the same Id in all languages, right?).
Tables Composite_Data_Types_IPage_Unpublished_<culture-code> still contain the translated pages.
However, for some reason only the default language tree shows all the pages. How can I fix this?
That page that is the new parent of the moved page hadn't been translated yet. It seems that the CMS does not display a translated child under the not translated parent. The steps that fixed the problem: 1. Translate the new parent page. 2. Click "Restart server". The translated child appears in the tree after the server is reloaded (the cache is cleared). Repeat these steps for every language.