My cat Mira is perfect, and has never done anything wrong. She also loves walking on laptop keys—both my MacBook and my wife Kathy's Windows PC .

You might think that walking on laptops is an example of Mira doing something wrong. She disagrees. And, in any case, we've both learned a lot about how our computers work because of this. Every time she walks across our keyboards she triggers some new, confusing keyboard shortcut. I wonder how she did it, but then I find out the keyboard shortcut by Googling around. Here's what I learned.

Mira Hides Important Things

Multiple times Mira has walked across my keyboard and caused most of my windows to disappear. This sends me into a panic—is my work gone?—until I click a dock icon and realize everything is still there. What happened?

It could be a few things. On the Mac the keyboard shortcut Command-Option-H hides all windows except the current one.…