Isolating hover tooltip information to just the glyph under the mouse

I have a plot with multiple lines. The lines are configured to use the same multi-column data source and the same “x” axis value, but each one uses a different column in the dataset for the y axis. Plotting works great.

Additionally, I have the hover tool enabled. Currently I have it configured in simple mode and set up to show all columns when hovering over any of the lines. I do that with a

[(x, '@" + x) for x in my_column_names]

mapping. That works great too.

The problem is that the tooltip is overloaded with information, and not helpful to inspect the specific line that the mouse cursor is over (and thereby triggered the tooltip/hover). To improve that, I’d like to either show just the one value for that one line. Alternatively, i’d like to write some custom HTML/JS code to keep all values but highlight the one corresponding to the hovered-over line. The problem in both cases is that I don’t see a way to get at the information about the hovered-over line. Is there a way to get that, either with a special $ or @ token, or in the JavaScript context at runtime in the browser? I added a little function in the custom tooltip HTML code and set a breakpoint on it, but when I inspect the variables accessible to the JS code at that point, I don’t see anything either.

I appreciate any tips.

By the way, Bokeh is amazing, thanks to everyone who contributed to it!