The Split Bars option interferes with the Y Axis Grouping, there should be an option to organise them separately.
Case: Heartbeat TCP connection metrics, can stack different connection metrics by adding them to the Y axis to create a visual split of an overall connection duration, very useful:
But then if you desire to split the bars by the host name of the connections and have the different connection hosts grouped side-by-side, however there is only one "bar mode" option which will then group everything side-by-side including each Y-Axis value and so it destroys the value of the stacked the Y axis and makes the chart impossible to read as it doubles or triples (depending on how many Y axis values) the number of bars for each host:
a) to be able to stack or group Y Axis and the Bar Split separately.
b) to be able to create further Bar Sub-Grouping on a single chart visualised as a hierarchy of grouping.