I think there is a missunderstanding.
Let’s say you have WaveLab and your workspace open (any).
You launch again. By design, WaveLab will restore the workspace as it was when you last quit.
Now, lets say you close it. And you create a new one. The layout as it was when you close it, is reused. Again by design. No default layout is used in all theses cases.
Now, another scenario:
Let’s say you have WaveLab and your workspace open. You close it (while some other workspace is open, ie. you don’t quit WaveLab).
Later you quit WaveLab.
You launch again. Now, if you want to create a new workspace, there is none that WaveLab can reuse. In that case, the default layout (if you have saved one), is used. And only in that case.