It doesn't appear on the list of active pens supported by the 7390 2-in-1.  Given that this model is older than the pen, that may be why -- or it may not be compatible.  Your best bet is to call Dell and ask, but my educated guess is that it's not supported.
anybody knows if this model dell active pen PN771M is suitable to use with XPS 13 7390 2in1 ? I saw this dell active pen PN771M in Dell retail store which comes together with the new Inspiron 13 2in1 model. The design of this pen is very easy to write and draw compared to PN579X.  Can see the pen from the link below. It is very nice and lightweight. [URL]#carousel-example-with-caption
Dell active pen PN771M