DVT SystemVerilog IDE User Guide
Rev. 18.1.40, 7 December 2018

42.27 How do I change the tooltip colors?

If you want to change the tooltip colors and GTK Themes are not available (Windows, MacOS) then you can use Preferences > General > Appearance > Colors and Fonts > DVT > Tooltips and for content assist Preferences > General > Appearance > Colors and Fonts > Basic'