Does the answer, I dunno work? In xlights, I pick a Bars effect, then pick the color picker and choose the purple that's on the right side (second from the bottom) on the basic colors screen. I did a paste of the effect below if that helps... only used effect1, and just checked that color only...
Bars,None,Effect 1,ID_SLIDER_SparkleFrequency=200,ID_SLIDER_Brightness=100,ID_SLIDER_Contrast=0,ID_SLIDER_EffectLayerMix=0,E1_SLIDER_Speed=13,E1_TEXTCTRL_Fadein=0.00,E1_TEXTCTRL_Fadeout=0.00,E1_CHECKBOX_FitToTime=0,E1_SLIDER_Bars_BarCount=1,E1_CHOICE_Bars_Direction=Right,E1_CHECKBOX_Bars_Highlight=0,E1_CHECKBOX_Bars_3D=0,E1_BUTTON_Palette1=#400080,E1_CHECKBOX_Palette1=1,E1_BUTTON_Palette2=#00FF00,E1_CHECKBOX_Palette2=0,E1_BUTTON_Palette3=#0000FF,E1_CHECKBOX_Palette3=0,E1_BUTTON_Palette4=#FFFF00,E1_CHECKBOX_Palette4=0,E1_BUTTON_Palette5=#FFFFFF,E1_CHECKBOX_Palette5=0,E1_BUTTON_Palette6=#000000,E1_CHECKBOX_Palette6=0,E2_SLIDER_Speed=14,E2_TEXTCTRL_Fadein=0.00,E2_TEXTCTRL_Fadeout=0.00,E2_CHECKBOX_FitToTime=0,E2_BUTTON_Palette1=#FF0000,E2_CHECKBOX_Palette1=1,E2_BUTTON_Palette2=#00FF00,E2_CHECKBOX_Palette2=0,E2_BUTTON_Palette3=#0000FF,E2_CHECKBOX_Palette3=0,E2_BUTTON_Palette4=#FFFF00,E2_CHECKBOX_Palette4=0,E2_BUTTON_Palette5=#FFFFFF,E2_CHECKBOX_Palette5=1,E2_BUTTON_Palette6=#000000,E2_CHECKBOX_Palette6=1