The History window is a unique and powerful feature for comparing settings in Ozone. To access the History list, click on the History button.
As you tweak controls, each movement is captured and displayed in the History list. To go back and hear a previous setting, simply click on the list at the point you want to audition. The changes that you've undone will show up in a lighter color. In the screenshot below, all changes after 9.6 dB of gain was added to band 1 in the dynamics module, etc. are undone.
Clear button: You can also press the Clear button to clear the history list at any time.
Close button: If you close the History window, processing resumes from the point you had last selected, so you can continue building on the History list from a earlier point.
A,B,C,D buttons: You can assign up to four points in the History list to A, B, C and D buttons. To do this, select the point in the list you want to capture, and click on the "Set" button below the A, B, C or D button. Clicking on the appropriate button will then recall the setting assigned to that button.
History Depth: The history list has a depth setting which controls how many edits it remembers. You can change this setting in the General Options tab .
When you exit Ozone, the History list and any settings assigned to the A, B, C or D buttons will be saved to the file iZOzone3.hst in the directory where you installed Ozone. The next time you start Ozone, the list will be remembered so you can pick up right where you left off.
While using Ozone, you can press Ctrl+Z repeatedly to undo edits you've made, and Ctrl+Y to redo edits. See Shortcut Keys and Mouse Support for more keyboard shortcuts.