[Ultimaker Cura 4.0 | Stable available!]

Uninstalled within 2 hours I use a custom printer Anet A8

Cura 4.0 did not recognise it had 1.73 mm filament set for the printer.

Adding a custom material did not show up in the materials list when created.

Created unprintable gcode.

Seems like custom printers and filaments are just messed up, I recall this seemed to be an issue in a previous version, was it 2.4?