Single Extruder Multi Material Mode does not ask for filament change and prints everything with first filament  

Single Extruder Multi Material Mode does not ask for filament change and prints everything with first filament

Hello,

im fairly new to 3d Printing but was able to print the awesome prusa rugged box lid with multicolor on input shaping without a problem.

However that came with a 3mf project file that had everything preconfigured.

Now i am trying to print an uno cardbox game variant of the rugged box with two colors and have enabled the Single Extruder Multi Material mode. I changed the colors of the extruders and in the slicer everything looks nice.

However when i start the print my MK4 just prints everything with the first filament and does not ask for a filament change.

I am thinking i only am missing a simple checkbox somewhere but cant figure it out.

Can someone here point me to the according setting?