We've made two changes to the page where you configure spreadsheet edits. The first is the addition of a Clear All button to reset all column mappings at once. When you upload a spreadsheet the app will try to guess which columns you want to edit but if you only want to edit one column this will save you from having to de-select each column.
The second change is that we've removed the column showing the number of matching products. We did this to save space and remove the need for excessive scrolling. Now, a warning will show up if a product matches more than one product or if it doesn't match any products at all:
Learn more about editing Shopify products with a spreadsheet.