Choosing the option "Use firmware retraction" in Printer/General only generates G10/G11 if the option "Retraction Length" in Printer/Extruder x is nonzero (not disabled).
In the 1.2.1 Version, selecting "Use firmware retraction" in Printer/General disables the box to set the retraction length (in my opinion, correct behaviour). If this field was previously set to zero, it is now locked at zero and not possible to change until firmware retraction option is unselected.
Steps to re-create:
Fixed regression causing retraction to be skipped when Retract Length…
… was 0 but Use Firmware Retraction was enabled. Includes regression test. #2359
Thank you, I fixed this and added a regression test.