Undo is implemented in Screen Writer Studio in a manner that is very simple and intuitive. However, since most other word processors implement undo as a limited sub-set of the Screen Writer Studio approach, it may be more difficult to understand. (The Screen Writer Studio approach is generally considered the best approach for undo. It’s just a lot more difficult to implement.)
When you interact with Screen Writer Studio, you do so by giving Screen Writer Studio commands. These commands come from keys you type and mouse commands. Some of these commands change the script, such as inserting a letter. Others come from bringing up dialog boxes, entering settings in the dialog box, and then pressing OK or another button in the dialog box.
Undo undoes your last command. It does not undo just some commands, it undoes all commands (except global spell checking which is covered below). If you press undo 3 times, it undoes your last 3 commands.
When you bring up a dialog box, it does not undo the actions you took within the dialog box. It undoes the changes in the script that occurred when you applied the dialog box to the script.
To undo a command you can select Edit, Undo or press CTRL-Z (hold down the CTRL key and press the Z key).
Also note that just moving the caret in the script is considered a change. The words in the script are the same but the position of the caret, or what is selected, has changed.
When you spell check the script, your previous undo history is lost. You cannot undo back past a spell check. This was done because you generally will not want to undo a script spell check. And if the spell check cannot be undone, then commands before the spell check cannot be undone.
Aside from that, any command can be undone. If you cheat the document or change the formatting of a paragraph style (shown in later tutorials), a single CTRL-Z will undo that command, reformatting the entire script. Undo also undoes what is in the clipboard.
Redo will cancel out the effects of an undo. Because it undoes an undo, you can only select redo right after an undo. To redo a command press CTRL-Y.
You can undo up to the last 30 commands. If this isn’t enough, you can increase this in options. You can also speed Screen Writer Studio up a little if you set this to 0. So if you never use undo, set it to 0. But try using it before you decide you will never need it.