Tapping the Tab key while in the Import dialog, toggles between Compact and Expanded view (or click the small triangle in the lower left of the Import window).
Just tried it using 3.3 RC and found out that tapping the Tab key going from Expanded view to Compact view it works fine, but going back to Expanded view does not. When starting the Import dialog in Compact view and tapping the Tab key does toggle it to Expanded view. Using Tab again brings me back to Compact view and after that it fails to work again.
Before I forget, using the Windows version.
Thank you for your feedback. I have forwarded it to the product manager for Lightroom. It would be greatly appreciated if you would report any additional issues using the Adobe Bug Report form (there is a link to it from this page, just click on the Product Details tab midway down the page):
I know that it’s a bit more effort, (and took me a few minutes to find!) but this way we are certain to get the necessary information to the correct person in order to try to duplicate the issue. Thanks again,