How to make all the legend symbols in black ?

The legend automatic in different colours.
How to make all the legend symbols in black ?
Does anyone has the clue ?
Thank you very much.
Yi
You will have to create your own legend using a textbox. Here is an example:
Make/N=10 wave0=gnoise(1), wave1=gnoise(1), wave2=gnoise(1), wave3=gnoise(1)
Display wave0, wave1, wave2, wave3
ModifyGraph mode=3
ModifyGraph marker(wave0)=19,marker(wave1)=16,marker(wave2)=17,marker(wave3)=23
TextBox/C/N=text0/A=MC "\\W519\twave0\r\\W516\twave1\r\\W517\twave2\r\\W523\twave3"


I generated the backslash-W codes using the Markers submenu of the Special popup menu in the Add Annotations dialog.