Options Dialog » History » Revision 21
It can be opened by pressing the ALT + O hotkey, by typing /options or by opening File -> Options in the Menubar.
AdiIRC has a lot of options which can be confusing, however the defaults are good enough in most cases.
You can narrow down the option you want by typing in the Searchbox at the top, it will mark the matches with a red rectangle.
Example search for "Spacing":
You can save options by pressing the "Save" button or press CTRL + S
AdiIRC will also warn you when closing the options window if there are any unsaved changes.
You can reset all options in all tabs by clicking the "Reset" button.
If you want to reset only one tab, you can right-click it in the listbox and chose "Reset".
Clicking the help icon, opens the help page for current selected tab with more information about each option.