Hi Manuel Carreira,
You still be told this is an English forum, please post your question in English .
After translating your posting, If you are tring to do someting with WPF and if I understand correctly,
Microsoft have not provided MDI Window in WPF, but you can use the third party source to do that.
Check this:https://wpfmdi.codeplex.com/
Sincerely,
Bob
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