[Bug] Evolution chart tooltip only shows max 8 colors

[Stan-vw]

What happened?

When you have more than 8 lines on an evolution chart and hover over one of the lines, the tooltip will only show colors for the first 8 line items.

What should happen?

Colors should be shown for all line items in the tooltip

How can this be reproduced?

1. Go to demo.matomo.org
2. On the dashboard, in the Visits Over Time evolution chart, add 8+ metrics to view
3. Hover over one of the lines in the chart

Matomo version

5.2.1

PHP version

No response

Server operating system

No response

What browsers are you seeing the problem on?

Chrome

Computer operating system

MacOS

Relevant log output

No response

Validations

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• Follow our Security Policy.
• Check that there isn't already an issue that reports the same bug to avoid creating duplicates.
• The provided steps to reproduce is a minimal reproducible of the Bug.

[michalkleiner]

At a guess, as the graph also only displays 8 lines, I'd say 8 is the limit and it should not allow to add more.

[Stan-vw]

The graph actually shows more than 8 lines. Unfortunately most of the lines in that chart/screenshot are just constantly zero, so you can't see them as they overlap. However, there's charts where you would see all 9+ lines.

It might be useful to share this screenshot that shows that the 9th and further lines do actually get assigned colors:

The problem is simply that this color is not shown in the hoverover tooltip.

Just guessing here, but I think it might be because there's only 8 colors available, and from there it starts cycling through the same colors again. On the screenshot above, the last 2 colors visually look identical to the first 2. Unfortunately I don't have a color picker at hand to verify 100%