NSAlert accessory view

I need to add an accessory view with a text field to an NSAlert. This works as expected but as my app comes in different languages, the alert looks a bit different depending on the language used:

So I wonder how I can make the text field automatically use the full width of the alert window. I tried to call the alert's layout method and then resize the text field but this seems not work in all cases. Any help would be highly appreciated. Thanks!

NSAlert accessory view
 
 
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