XnView Software

If I apply FusionDark theme everything is OK, except background colors for preview window and full-screen.
(Browser background not changed too, but Thumbnail Cell>Background can be disabled for better theme appearance)
This force me to use different INI files for dark and light themes if I want fully synchronized colors.
Is there a way theme to control background colors or I miss something?

If thumbnail cell background is disabled - default background color from Theme is exposed. There are 3 more background colors in Settings:
Browser > Preview Background Color
View>Background Color
Fullscreen>Background Color
If these 3 have same settings as in thumbnail cell>background. e.g checkbox to disable Background color. I think this will expose the default theme color.
Is this possible ?
Themes will have finished look this way - one unified background for all windows (with all current customization possibilities).

One more question:
Pierre, is it possible to define transparent color in INI? What is the code for 100% transparency (if any)?