Update = 8/9/19
Unfortunately, you purchased a Non-Pen Enabled panel. To be compatible with any Pen, the Inspiron 5579 must have been purchased with one of these more expensive Pen-Enabled panels =
FH64T LCD, Touch Screen, 15.0 FHD, Truelife, EDP1.2, Pen
TN7DT LCD, Touch Screen, 15.0 FHD, Antiglare, EDP1.2, Pen
Yes, you bought a compatible system, but you did not purchase the more expensive compatible LCD panel. If you had purchased the compatible LCD panel, you would have the label stating, ""Support Active Pen".