Normally, RainPro can generate the key automatically from the chart you have plotted, for example if you plot a bar chart and a line graph the key will be preset to a small shaded block and a line (and/or marker) of the appropriate type and colour. If for some reason you want to ‘hand craft’ a key you can use this property to set the type of placeholder:

chSet 'Ktype' 'Bar'
chSet 'Ktype' 'Line,marker'

This will pick up the current settings of the colour, marker and pattern cycle – to get a key in a particular colour sequence you must include a Colours setting just before you write the key.

See also ...
chWriteKey – output key at given location
Colours – set colour cycle