On Portal UI, click on "Monitor", Select Apps and Click "Print", the "Print" preview cannot show the complete traffic trend for app chart.
This is due to the print settings of the browser -- the scaling is not correct.
Reduce the Scale on print settings to show/print the full page
The following example is for Chrome, other browsers are similar,
1. expend "More settings"
2. change the value of "Scale" until the charts are showed completely.