Currently, if I have the default language for a project set to English, and I create a new action button, that Action button gets created with the caption Action, and it automatically gets a Dutch translation of Actie. That is fine, but if I then change the caption of the button in English to, for instance, 'Cancel', which is already a known term (149 usages) with a translation to 'Annuleren' in the project, it doesn't automatically change the Dutch translation to 'Annuleren', it leaves it as 'Actie'. This also goes for the situation where you clear a caption of a button in the default language for the project, it does not clear the translations, so you can have a blank caption in the default language and then something like 'Actie' in the Dutch translation, which doesn't make sense.
This makes it really difficult to keep track of translations if I have to continually search for terms that I know have already been translated or that don't even exist anymore in the default language.
I agree that there should be a setting to turn off the automatic Dutch translations, but also I think this should be a bit more dynamic, and when you update a text in the default language, it should check to see if there are available translations for the new text and if so, it should change the translation for that item to the translation that exists in the system. Or if you clear the text in the source language, it should clear it in the translations. Because why would you want it blank in the source language, but to have text in all the translations?
I have had quite a few discussions about this with Mendix before. Last one was on a idea forum topic. This problem is mainly in Dutch, because other languages, like French or German, don't get a default when you create a button. General idea was back then to not set the default in Dutch when it is not the default language, so: project has US English as default, language selection is set to US English. When I create an action button, Dutch will not get a caption set, so it will have the English caption as default, like any other label or text.
I really hope that this will get implemented in the near future. Same applies for any button, also for groupbox captions.