Reproduction steps

1. Login as admin
2. go to the Panels section of the Administration
3. drag-and-drop all Panels from a column (either left or right)
4. save
5. Visit a page

Expected

The columns are displayed without any content (i.e., there is some margin between the main content and the side).

Actual

1. The column is missing
2. There is no padding between the main content and the side
3. Going back to the Panels section of the Administration, the panel columns is "No side column" (given all the panels have been removed at step 3)