How to create a new pattern fill (two-color)?

Hi all,

Whatever I try I am not able to create a new two-color pattern fill in coreldraw 2017.

I do the following:

"edit > create > Pattern Fill"

then I select "Two-color" and "Low" (or "Medium"/"High", in Resolution)

I select an area, then a message appears "Create pattern with selected area?". If I click "OK" nothing happens (it does quite the editor but apart from that nothing...)

Am I doing something wrong? Do I have to select an area that contains a specific object or ...???

Any help is very much appreciated!