Hiding column between merge cell

I was in my client's office the other day and she told me that she cannot hide the column when there is a merge cell in one of the rows. For example, there is a merge cell D1:F1. She wants to hide the column E. What she did was to click on the column header which highlight the entire column. As D1:F1 is a merged cell, the entire merged cell is highlighted. When she clicks on the right mouse button and chooses hide, a error message pops up. The error is due to the merge cell. As such, she has to resort to unmerge the cells D1:F1, hide the column E and remerge the 3 cells.

There is an easier way and here it is.

Select any cell in column E other than that in row 1 which contains the merge cells. For example, E2. Then go to the menu bar and select format, column, hide. The column E is hidden. Don't need to unmerge the cell at all.