Rainbow contains several visual improvements for your charts. First of all it’s bar width handling, which prevents bars overlapping or bars being too thin. The bar width is handled automatically even for multiseries charts, where Rainbow keeps the same bar width for all data series in case all of them have the same bar type/period settings. This is designed for candlestick bars, so if you don’t like it you can turn it off by parameter “Visuals+/Tweak bar widths”. There is also an option to keep the price above other indicators and chart objects, which is enabled by default.
If you look into dataseries “Chart style” option, you’ll find Rainbow’s enhanced Candlestick+ chart style, that allows you to separately define outline colors for up & down bars. The style is selected as can be seen in the picture: