I have made a workaround for this bug.
I have added a button, "Collapse Sidebar" at the bottom of the page. When you click it, the sidebar is collapsed and the content expands. The text of the button now becomes "Expand Sidebar". Click it, and the sidebar re-appears.
In this way, if there is any overflow, you can just scroll to the bottom of the page, collapse the sidebar, scroll back up to the overflowing post, and do whatever you want. This should fix most of the (very rare) problems with overflows.