Description
trace.hoverinfo has two special values: 'skip' blocks hover labels AND hover events, and 'none' blocks hover labels but still emits events (or includes this trace in events with multiple traces). For "compare mode" hovermode: 'x' this works correctly, but for unified mode hovermode: 'x unified' the trace symbols still appear, just with no text. This happens even if ALL the traces have hoverinfo: 'none', but if one trace has hoverinfo: 'skip' it seems that this trace gets filtered out of the unified hover label, and sometimes it takes away some of the hoverinfo: 'none' labels with it.
As saved, the following codepen has hoverinfo: 'none'/undefined/'none' (for the three traces in the first graph) and you see all three trace symbols but text only on the second. The correct behavior would be to only see the symbol and text for the second.
If you set all of them to 'none', you see three symbols and no text. The correct behavior would be no hover label at all.
If you set 'none'/'skip'/'none' you see the first and third symbols and no text. The correct behavior would be no hover label at all.
If you set 'skip'/undefined/'none' you see just the second symbol and its text. This is the correct behavior, strangely enough!
If you set 'skip/'none'/'none' you see the second and third symbols and no text. The correct behavior would be no hover label at all.
https://codepen.io/alexcjohnson/pen/mdOBjVz?editors=1010
