When you have a graph that has VictoryBar components all on the same axis using VictoryStack, you cannot adjust the width/size of the bars.
Once you add other bars on a different axis, then you can change the widths and everything, so this problem only occurs when there's a _single_ stack of bars.

@nickzuber thank you for this issue. I will get this fixed for the next release
@boygirl Thanks! 😄
Actually, after taking a closer look at your sandbox, this is not an issue with the library.
The width prop on VictoryBar refers to the overall svg width, not the bar width. To define the bar width, you should add a width attribute to your data styles like
style={{ data: { width: 20 } }}
You can add that prop on either VictoryStack or VictoryBar, or both, but conflicting styles defined on VictoryBar will take precedence.
@boygirl Ah I see, that definitely does the trick — thank you! I wish that could somehow be more clear in the docs
@nickzuber Definitely. I'm thinking of adding a barWidth prop so that styles are restricted to valid svg styles