Several Russian translation bugs:
"Delete layer" in the history should be translated as "Удаление слоя", not "Уделение слоя".
"Background" layer should be translated as "Фон", not "Справочная информация".
Settings > Updates: "Также проверьте наличие бета-версиями paint.net" should be "Также проверять наличие бета-версий paint.net"
Settings > Diagnostics: the property sheet columns "Item", "Value" are not translated.
Settings: "User Interface" in Russian is "Пользовательский интерфейс" which is too long for the fixed-width menu; better replace with just "Интерфейс" (that is how VLC player translates "UI settings" in its menus).
Settings > Diagnostics: "Open crash log folder" should be translated as "Открыть папку журнала падений" or "Открыть папку журнала ошибок", not "Папка журнала открытые краш".
Plus, confirming the mentioned bug for any non-English initial language:
Thanks for the best free Photoshop replacement!