Well, that is part of the icon, that's not just background.

But there should be support for mono version #352 but you're one minor version and three patches behind. Can you double check if you can see the mono icon with the AppImage or any other continuous build package?

I installed 1.9.1-1~bpo11+1 from bullseye-backports and got an error:

$ ksnip
ksnip: symbol lookup error: ksnip: undefined symbol: _ZN15kImageAnnotator15KImageAnnotator38setNumberToolSeedChangeUpdatesAllItemsEb

Not sure if that is going to work, looks like you're missing the matching annotator, probably a version mismatch. What I meant with continuous is this here https://github.com/ksnip/ksnip/releases
Those packages are build by us and should contain all you need.

Yes, it's works, but the tray icon is the same anyway. =(

Ok, for some reason we fail to detect there that you're using dark mode. Requires some investigation.

May be the better solution would be suggest a selection of an icon at tray in the application settings?

This is my environment: https://github.com/bupy7/my-openbox-wm May be it'll helps you.

Most applications do that automatically, like Telegram there, you probably haven't set icon to white. We do that by checking the color of the application palette here https://github.com/ksnip/ksnip/blob/31348873b914502adce6e1e97812f7704b479a7e/src/common/loader/IconLoader.cpp

One question though, can you share a screenshot of ksnip? What color has ksnip?

I'm using dark colors only for tint2. For windows I'm using light theme - Raleigh GTK Theme.

And I'm using Papirus icons and Telegram are using its too for the tray icon.

Well that explains it, the application palette is light so we think we're not running in dark mode. Maybe we need some changed logic to look at every widget, in this case the tray icon and use that for the check.

И я использую значки Papirus...

спасибо за хорошую программу. она мне нужна. раньше. я не знал о её существовании.
ksnip - была чёрная иконка но данной программе её нет.