In the Layout tab, when you select a region under Explore Regions, it highlights the selected region in the template. Often times, especially when the template has many regions, the selected region is either not highlighted clearly or has no width or height and is hard to edit. The workaround is to temporarily add in a height or width to make is easily accessible.
Instead, it would be great if in the Explore Regions tab, when selected, only that region is available in the work area. That would avoid the confusion of accidentally editing the wrong region. Once you click out of the Explore Region tab, you go back to your usual full template view.
What if, instead of having only that region visible in the page, we had an Edit and Delete button in the Explore regions tray when you selected the region? Much like it behaves in the page, when the region is selected, the Edit and Delete icons could appear for that item in the Explore Regions tray allowing you to quickly show the edit or delete dialog depending on your click.
One of the problems I have most, is that the region outlines are very very fine in width. It may also help if you could make the region outlines a few pt sizes thicker.