when you click a new tool or text on the resource palette it will has different actions depending on what you click. It will "tabify" like with like, and zonify unlike.
eg. if you have a text open (let's say ESVS, then you select another text, it should open in a tab. This is normal behaviour. likewise if you have a tool open, and you click a tool. Zones gather like modules.
you can then (usually) create a new zone with that tabbed text or tool by dragging it to a place where accordance suggests (by giving you a sort of ghosted window position). If you can't it suggests you may have too many zones already open in a display that can't quite cope. A zone needs a minimum amount of space and will not open if there's not enough.
First, try just opening a new workspace from the File menu. That should only have one text in it (usually the ESVS, but it depends on what you have set up the default to be). Then do a CMD-N which will open a second text in a tab. Now try and drag that into a new zone.
To help us help you, what Mac are you using? What version of Accordance 9? What version of Mac OS?
Could you possibly save and then upload your workspace to the forum (using "More Reply Options" below)