It's an excellent question.

Many of the dialogs have been changed from 'modal' meaning that you have to interact with the dialog before moving on, to 'non-modal', which means that the dialog can stay open while you perform other tasks.

As a result of this, some things like 'OK', 'Apply' etc no longer behave the same way.

Ideally, some of these should have been changed to 'Save and Close' or similar, but that's not the case, so the only way to close these dialogs is by pressing the red 'X' in the top RH Corner,

I hope this helps to explain the new operations.

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