In Windows Explorer, I tried to associate .txt files with Sublime using right click the file -> Open with -> Choose default program -> from there choosed sublimetext.exe. It works, but opening files this way takes about 10 seconds even if Sublime Text is already running. Opening files from Sublime's own File->Open menu is snappy and fast.
Obviously there's something wrong with the way I'm associating the files; maybe it tries to start another instance of Sublime (which obviously takes time), and then at some later point it notices that there's already one instance running, and then opens the file with it. Is there any way to speed up this process?
Otherwise, what a magnificent editor!