Preview Mode is one of the best interface features of InDesign. Preview Mode hides all non-printing items such as ruler guides, hidden characters, frame edges and text threads. I love being able to layout pages with all of this helpful non-printing stuff displayed, but when it gets in the way of being able to visualize my design, I can hide it all with a single keystroke. Unfortunately, the default keyboard shortcut to switch into and out of Preview Mode is "w". Since this is a single-letter keyboard shortcut, it doesn't work if you are editing or typing text with the Type tool.
InDesign CS3 provides an entry point so that you can change this keyboard shortcut to something that will work all the time, even when you are editing text. Here's how:
1. Choose Edit > Keyboard Shortcuts
2. Choose Tools for the "Product Area"
3. Choose Toggle view setting between default and preview in the list of commands
4. Click in the "New Shortcut" field, and press the keyboard shortcut you want to use (I use option-shift-w on my Mac and alt-shift-w on my Windows computer).
5. Click the Assign button. You may be asked if you want to create a new set. If so, answer Yes.
6. Click the OK button.
Now, if your new keyboard shortcut includes modifier keys such as option, alt, command or ctrl, you will be able to use the keyboard shortcut even when you are editing text. Once you get used to this, you will find yourself switching between Preview Mode and Normal Mode quickly and easily whenever you feel the need.