What worked:
Edit `filetypes.cs` and remove this block:
``` [build_settings] # %f will be replaced by the complete filename # %e will be replaced by the filename without extension # be careful following settings are untested compiler=mcs /t:winexe "%f" /r:System,System.Drawing run_cmd=mono "%e.exe" ```
Replace it with something like this:
``` [build-menu] FT_00_LB=_Compile FT_00_CM=csc /t:winexe "%f" /r:System,System.Drawing FT_00_WD= FT_01_LB=_Build FT_01_CM=csc /t:winexe "%f" /r:System,System.Drawing FT_01_WD= EX_00_LB=_Run EX_00_CM="./%e" EX_00_WD= ```