XPS 13 9360 - MS Office screen resolution on external monitor

Hello,

I purchased XPS 13 9360 two weeks ago.

I have a screen resolution problem (blur, not clear) for all MS Office applications on external monitor (HP Pavilion 27xw).

Video driver is up to date (Intel HD graphics 620). I called DELL support but they ask me to pay as the problem occurs only for MS Office applications.

I searched online and found one solution which I need to make external monitor as "Main Display".

Then MS-Office application will have same problem on my laptop screen.

Please help! Is this really MS-Office problem?