It would be useful to be able to change the background colour and transparency of the tooltip to highlight and colour-code, and to allow parts of the visual to be seen behind it. The latter would be ...
'Native, dark tooltip give very awesome UX when background is configured slightly transparent. Power BI propose to configure transparency, both : - in the parent visual's "tooltip / background" section (usually) - in the tooltip page's background setting Bur none of them end up with some transparency on the actual tooltip. This is not rational (big ?). And this is disapointing.
