This issue may seem minor but still it became quite annoying for our project.
The reason is that when UltraExpandable box is docked bottom it displays buttons/icons (arrows) that collapse/expand the box the same way as when any other (horizontal) docking is specified, though the behavior of expansion/collapsing is different.
This only occurs when ViewStyle is Office2003, Office2007, VS2005.

Repro:

1. Add UltraExpandableBox to the form.
2. Set Dock as None and place it in the bottom of the form and leave it expanded.
3. Note how collapsing icon is displayed (see ok_exp.png). The arrows point up meaning that on clicking the box contents would roll up.
4. Click on the expanding button - contents roll up, header stays on the same place.
5. Note how expanding icon is displayed (see ok_col.png). The arrows point down meaning that on clicking the box contents would roll down.

6. Dock UltraExpandableBox to Bottom.
7. Try expanding/collapsing and note that the header goes in the bottom of the form when being collapsed.
8. In the expanded state (see !ok_exp.png) the header would roll down (visually) in the next step leaving the header in the bottom of the form. In the same time arrows still point up.
9. Collapse UltraExpandableBox.
10. Note that arrows in the button now point down, though expansion behavior would result in rolling up.