Hi Makaur01,
Yes, absolutely. Every time you add new functionality to existing, you should always test ALL functionality.
You need to check that it still works with the new functionality added (that it hasn't somehow knocked it out of sync). Does it look out of place with the old functionality. Do they have different 'Back' buttons for example. In which case they are out of sync with each other.
So yes, is my answer. Test it all.
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