[Highlighters][Color Picker]: can't approve color selection by double click
OS: Windows 10 LTSC (version 1809) x64
App Version: 21.08.0.1154

That dialog comes from Qt. Unfortunately, there is no way to handle double click in klogg.
There might be a custom color picker widget that works with double clicks. I've checked https://mattbas.gitlab.io/Qt-Color-Widgets/, but on the screenshots there is no panel with basic/custom colors out of the box. It can be added
but on the screenshots there is no panel with basic/custom colors out of the box
It's ColorPaletteWidget and Swatch widget, isn't it?
At least I guess that you can predefine default color palette which can be changed to user's one