SYMPTOM:
Disable the privilege “Web set column widths” in the Web professional privileges

When viewing a document in Presentation Mode, the user can still resize columns by selecting and dragging columns borders

CAUSE:
The cause of the issue is unknown. This issue can be reproduced in 10.4 and 10.7 but cannot be reproduced in 10.3.
The issue is fixed in 10.8
KB439729