The Dangers of Hidden Information

Do not hide anything except some sheets. Excel has too many attractive options that look good but may be risky in the long run. In Guideline 6, we already advised you not to use the functionality which allow you to merge cells, or to only do so when it’s necessary. In this guideline we talk about the dangers of hidden information.

Excel Guideline 08: The Dangers of Hidden Information :: PerfectXL

A little exercise

Open a new document in Excel and enter a value in the cells A1 and B1. Use “=A1+B1” to add them in cell C1 and then hide column B. Now copy A1: C1 (which now looks like 2 cells) to somewhere else in the worksheet. Three newly filled cells appear. Logical, if you think about it, but surprising and dangerous if you were unaware of the hidden column.

There are many ways you can hide stuff in Excel:

  • You can hide columns or rows. One or more at a time;
  • You can hide information by giving the text and background the same color;
  • You can also hide information using the custom number format feature. By typing in“;;;” under custom number formatting your information is made hidden;
  • With cell properties -> protection -> hidden, you will not see the underlying formulas of cells after you have protected the worksheet. The result is still displayed in the cell, but the formula bar remains empty;
  • You can also hide entire tabs;
  • Finally, you can make a tab – seriously – very hidden through the developer menu and the VBA code page. Then you can not retrieve a this tab with right-click but only through this VBA screen.

We think there is only 1 way of hiding information that is acceptable and often even wise: hiding entire tabs (not very hidden). The dangers of clip and insertion problems are minimal as the whole sheet is hidden. The user-friendliness of the spreadsheet is really increased and, with the right-click button on one of the tabs, it’s easy to see which tabs are exactly hidden. Even in this situation we suggest you clearly notify the user in the documentation sheet that the tab exists and is hidden.

Excel Guideline 08: The Dangers of Hidden Information :: PerfectXL

What to do with complicated calculations?

This situation is fairly common: you have some input numbers, a series of calculation steps and a result. All those steps can be confusing to the user who didn’t create the sheet. Hiding the calculation columns seems attractive but think back to Guideline 4: Distinguish between input, calculation, and output sheets. If you head the advice in that guideline, hiding calculations is not necessary. This is much easier to maintain and it’s a more stable solution than hiding columns.

How can PerfectXL help you?

Suppose you get a spreadsheet with all kinds of hidden information, try the PerfectXL add-in! In the menu bar of the add-in you will find a button “Unhide Everything”. All rows, columns, and hidden or very hidden tabs will be made visible. What’s nice is that, the button remembers what has been made visible and changes itself into “Rehide,” when you click on this, all information goes back to the way it was. In addition, the risk overview of PerfectXL can also help you: Once you’ve analyzed your sheet you can find a list of all hidden information in the risk overview.

Excel Guideline 08: The Dangers of Hidden Information :: PerfectXL

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