HOw do I open the audio montage tab window

Title says it!

FYI

I imported an empty audio montage from WL 9.5
No tabs in the audio montage window.

WHen I create a new montage in WL 10, I get the tabs

Import? There is an “Open” command, not an “Import” command. Try to drag and drop the 9.5 montage to WaveLab 10.
And make sure to use WaveLab 10.0.20