1. Enter some folder with many subfolders (there must be more than two columns in explorer panel).
2. Navigate no e.g. third column.
3. Enter some folder.
4. Press Ctrl+PgUp or Ctrl+PgDn.
5. Leave folder.
Result: explorer panel is unscrollable anymore (at lest by cursor keys) until you enter and leave some folder in the first two columns or parent folder.
Video attached (rename to .7z).
---
P.S. Although Ctrl+PgUp and Ctrl+PgDn are used for moving to sibling folder, they are allowed to be shortcuts in the keyboard customization. But don't work.
On the attached pic. you can see how the keyboard customization dialog looks after assigning Ctrl+PgDn key on View - Menu Bar
