Hi Mirek,

I only just a couple of days ago updated my Windows 10 to version 1809, which introduced Dark Theme support in Windows File Explorer, which is not a store app, but a desktop application. (This was not available in 1803.) This IMO proves that Microsoft is just in the middle of transition of Windows 10 desktop theming. (E.g. Wordpad and Notepad do not have a clue about the Light/Dark mode.) I would expect Microsoft to release some documentation about how this Dark/Light theme support is supposed to be done on Windows 10 with desktop applications. (Unless they have and I just could not find it, of course.)

I think the non-client areas are controlled by DWM which can use the user selected accent color to draw the caption. Just select "Personalize > Colors > Show accent color on the following surfaces > [V] Title bars and window borders". And this is up to Windows and the user to select and handle anyway. U++ is only responsible for painting the client area.

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In my opinion, just basic handling of Dark/Light theme in a way that makes the application to fit in is enough. In case of Windows 10, it is all about using the knowledge of Windows Dark/Light mode, the Colorization color and the Accent color. (For those functions I posted the code earlier here.) Everything else could be solved from there. Nothing fancy, just the basics.

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In the end of the day, this is not a high priority issue for me. I can largely live on light theme too. I just have the feeling that the dark theme is slowly emerging and it will need sufficient support, but maybe not this month yet.

Best regards,

Tom