The sidebar will go outside the screen when open a long thin picture, the scrollable sidebar on the right side exceed the screen. e.g. The picture with width 419 and height 7485, then the sidebar will definitely go out the screen unless you have a extremely long screen like  iPhone 200 ;)

Reproducible: Always

Steps to Reproduce:
1.open an extremely long picture
2.display the picture as actual size sidebar
3.done
Actual Results:  
sidebar go outside of the screen

Expected Results:  
sidebar within the screen but the actual height of the sidebar should be compressed