How to add translation for TinyMCE?

Question

JavaScript

In Yii2, the TinyMCE widget is added to the page, and image_upload is also connected.
Translation for buttons in image uploader added when connecting widget:

'init_instance_callback' => new \yii\web\JsExpression("
                    function(editor) {
                        tinymce.i18n.data.uk_UA['Upload'] = 'Завантажити';
                        tinymce.i18n.data.uk_UA['Image'] = 'Зображення';
                        tinymce.i18n.data.uk_UA['Drop an image here'] = 'Свой текст';
                    }
                "),

But the text Drop an image here didn't translate. Why and how to fix it?

Answer 1

It looks like this text is wired into layout.