We have mixed feelings about dual-screen devices. The dual-screen Kyocera Echo landed rather flatly, despite its unique form-factor, and though we’re excited to see Sony’s folding S2 tablet up close, we’re still hesitant about all those hinges and springs. But Microsoft seems to be flirting with the idea of it, filing a patent that describes a dual-screen device (possibly a smartphone) with one display that can be detached.