Question: I'm new to jedit, and I haven't yet found out how to open a new window. For example, I want to be editing one set of files in one space on my Mac, and edit a different set of files in another. Does anyone know how to open a new instance/window of jedit to make this possible?

Thanks

Answer: 
You should set **Buffer Sets** scope to "**View**"

See also: [Buffer Sets](http://www.jedit.org/users-guide/buffersets.html)
It's a new feature to 4.3. It's under View | Buffer Sets. You click on either the "View Scope" or "EditPane Scope" buffer sets checkbox. 

When you open a new View, it's a separate window instance. It has a buffer set and an edit pane. With more than one View open, you can decide to share buffer sets (global scope) or each keep their own (View scope). When you split the View, you add another Edit pane. Each can use the View's buffer set, or have their own (EditPane scope)

Global scope: All Views and EditPanes share a common buffer set  

View Scope: EditPanes in the same view share the same buffer set  

EditPane Scope: Each EditPane can have it's own independent buffer set.

The editpane scope works when you have split the view (view | splitting). You can look at files side-by-side, and each side can have their own buffer set. Very useful in comparing files in two different directories (one set per side), for example.