Open a new windows notepad, type “this app can break”. Save it. Reopen the file. Voila. Only works with that precise text. Very strange!
Well there is an explanation – notepad doesn’t know which encoding the file is and it does an ad hoc test. If your text coincides with another encoding (in this case some kind of chinese hexograms), then it gets interpreted as such. If you don’t have that installed, you see the squares…