plot.ly Hover Box Size attribute

You probably found an answer since but :

By setting 'text' and passing it to your hoverinfo. In your example if you set text='CollegeClass' and set your hoverinfo = 'text' you will get the result you expect. It seems that the name of the trace get truncated while the text or label that you pass isn't.

data = [
go.Scatter(
    x=[0, 1, 2],
    y=[1, 3, 2],
    mode='markers',
    text=['Text A', 'Text B', 'Text C']
    hoverinfo = 'text'
)]

Copied from https://plot.ly/python/text-and-annotations/#adding-hover-text-to-data-in-line-and-scatter-plots Not that in my case I had to set hoverinfo = 'text' while in the example it seems to work without.

I might be a little late but I found a batter solution Adding hoverlabel: {namelength :-1} into my trace object did the trick.

From Here