How to define the Y axis visualization of a barchart in the query

I have put together a query on event log data that I like that gives me the top 10 errors and warnings gathered from event logs by Computer, EventID, Source, EventLevelName, RenderedDescription.

Is there a way I can force the way the barchart visualizes the data in the query? 

Here's how the current query aggregates the data:

 

| summarize Occurances=count() by Computer, EventID, Source, EventLevelName, RenderedDescription

| order by Occurances desc nulls last

| take 10

| render barchart kind=stacked

The barchart heading then shows "Table Chart Stacked Column Computer EventID Source Sum", so the Computer is the X axis, EventID is the y axis, and Source is the graphed value.  

 

 

I want "Occurances" as the Y axis so I click the drop down next to "EventID" and select "Occurances" to get it to do that.  Then the heading shows "Table Chart Stacked Column Computer EventID Source Sum".   

 

I suspect I need to change something in the "summarize" clause, or the order by clause, but I'm struggling to figure out what I'm missing.    How can I make the chart render with Occurances as the Y axis instead of EventID?