At my work we still deploy web files the old-fashioned way, copying newer versions over from dev to test and test to prod. For comparing and copying changed files we use WinMerge. Although our workflow sucks, WinMerge itself is actually a nifty little tool for comparing any sort of text files. But today it pissed me off in a way it never has before. I copied a diff from left to right and then meant to save it with Ctrl + S, but accidentally pressed Ctrl + D. Guess what happened? To my horror, both sides went completely blank! It looked as if the file contents had been deleted, and undo had no effect. To my relief, the files were intact when opening them in VS Code. Thinking this was a glitch in WinMerge, I restarted it but still, all files were blank. No contents displayed! Then I thought, perhaps pressing Ctrl + D again would bring the file contents back into view. And it did! So the bottom line is: Pressing Ctrl + D makes the compared files appear as empty. Now, who would want that to happen? What a nice feature, you've got here WinMerge! (I'm being sarcastic in case you missed that)