There aren’t any settings that will let you put space between the bars. You can get around this by using the Bin Data command from the Functions menu. Use Histogram as the Export Format. This will enable you to create a Column plot of the binned data. The Column plots let you have space between the bars.
KaleidaGraph is a thoughtfully designed graphing and data analysis application for research scientists, as well as for those in business and engineering fields. It produces publication-quality graphs, and easily converts the most complex data into a functional display.