Limiting Flashing When Using IDL at PPPL

Flashing happens when different X applications allocate competing private color maps. It is most noticeable on older 8-bit or 256-color displays.

On constrained displays, the practical PPPL workaround was to call mk_color before opening graphics windows: 

IDL> dummy = mk_color('yellow')

# for simpler sessions
IDL> dummy = mk_color(max=12)
24-bit Displays

If your display supports 24-bit color, use that mode. Avoid 16-bit color with older IDL workflows. 

IDL> dummy = mk_color(max=256)

See also simple color handling outside PPPL.

Other Options 
alias netscape 'netscape -ncols 64 -no-about-splash &'
idl.gr_visual: PseudoColor
idl.colors: 60

Those settings reflect older X11-era desktops but are kept here because they still explain why the original cluster notes were written the way they were.