One of the great consciousness-altering moments of the 20th century was the introduction of the Undo command. After a long day in front of the computer, the ability to undo any action seems quite natural. (Unfortunately, reaching for the Ctrl+Z keys after spilling grape juice on Grandma's antique tablecloth still doesn't work in the real world.)
Fortunately, most steps you take in Dreamweaver can be reversed with either the Undo command or the History panel.
Like most computer programs these days, Dreamweaver lets you undo the last step you took by pressing Ctrl+Z ( -Z), or by choosing Edit Undo. (This command changes to reflect your most recent action. If you just deleted some text, for example, it says Edit Undo Delete.) When youre feeling indecisive, you can redo the action you just undid by choosing Edit Redo or by pressing Ctrl+Y ( -Y).
You may wonder why the Preferences setting for the Undo command refers to "History Steps." It's because Dreamweaver creates a history for a document as you work on it. Each time you add text, insert a graphic, change the background color of the page, or do anything else to a document, Dreamweaver adds a new step to a list of previous actions.
All of these steps are listed in the History panel (see Figure 2-8). To see it, choose Window History, or press Shift+F10.
Each row in the panel represents one action or step, and includes a description. For instance, hitting Return or Enter while typing in the document creates a step called New Paragraph. Steps are listed in the order you perform your actions, with the latest actions at the bottom and earliest action at the top of the list.
But the History panel isn't just a dull document to pore overit's a living, multiple-step Undo command. Use the History slider to move to any step in the history list. To undo one action, for example, drag the slider up one step. When you do this, you'll notice that the slider's former position step is grayed out. Steps that are dimmed represent future steps, so moving the slider down one step is the equivalent of choosing Edit Redo.
You can undo or redo multiple steps by moving the slider up or down the list. Alternatively, you can click the track to the left of a step to move the slider to that step.
If you want to eliminate all the history steps for a documentto free up some of your computer's memory, for exampleselect Clear History from the History panel's context menu. But be careful: this is the one action you can't undo.