HI,
I created the same widgets as yours:
If you don't want the chart to be divided into series, keep it set to None.
The values shown on the chart are actually the number of seconds - i.e. in my example (250 * 60 + 14) * 60 = 900,000
I agree it should be presented as time values. We will fix it.
If you want all bars to be with fixed color, you can change it under the Customize topic.
The "time range" you used on the table, is the min and max values of this field. in your case is the time of the first and the last logs, and these are not the same as the duration. For example, there can be a single log to report on user activity of a few hours.