Due to a problem in the Quartus® Prime Pro Edition Software version 24.1, choosing between Qrun or Traditional flows in the ModelSim flow selection option is disabled after launching the Generate Testbench System in Platform Designer. This problem happens when the Create simulation model option in the Generate HDL window is set to None.
To work around this problem:
1. Click the Cancel button in the Generate Testbench System window.
2. Open the Generate HDL window and set the Create simulation model option to either Verilog or VHDL.
3. Click the Cancel button in the Generate HDL window.
4. Re-open the Generate Testbench System window and choose either Qrun or Traditional in the ModelSim flow selection option.
This problem is fixed beginning with the Quartus® Prime Pro Edition Software version 24.3.