If you’re the extremely lucky owner of a standard 101-key (non-Windows) keyboard, then you may have noticed the apparent absence of an equivalent to the „Option“ key (normally the left Windows key).
However, on any keyboard (101-key or Windows) you will find that the right-control key performs an identical function. Holding down the right-control key will let you type characters from various languages, plus many useful symbols. In addition, holding the right -control key while clicking the „up“ button or a directory in OpenTracker will open the directory in a new window.
The only downside to this approach is that the right-control key is in a slightly more awkward position than the real Option key, although I hope you’ll agree that the absence of the Windows logo on the keyboard more than makes up for this minor inconvenience ;)
See also:

Grok keymappings for Windows keyboards
Typing symbols in StyledEdit and other apps