Hi,
Are you opening that document within Word Online App? I see we only have Editing View and Reading View in Word Online. Please first check the size of your document under PAGE LAYOUT.
Please first try with a different browser and see if issue presists.
I would suggest you to install any updates that available to your Windows system, include updating the graphics driver. Then try again.
If I have understood you incorrectly, please feel free to post back.
Thanks,
Ethan Hua CHN
TechNet Community Support
