How can i use the hbrbackground member of wndclassex to change for example the color of the border? I tried mov dword [wndclassex.hbrbackground], COLOR_ACTIVEBORDER+1 but then the background changes and not the border.

dv4-fa,

Border is a non-client area of a window. Hence, WM_NCPAINT is the way to go.

Thanks, but i already know about wm_ncpaint.

Wndclassex: http://msdn.microsoft.com/en-us/library/windows/desktop/ms633577(v=vs.85).aspx.

looking at this msdn page at the hbrbackground member info it says something about color_background btnface highlight etc (convert to hbrush??? How???).. What i wanna do is use wndclassex to initialize the dialog with set colorscheme for border, highlight on button etc. For that specific window. because setsystemcolors never works for me.

To completely override the dialog colors most likely you need to draw in response to WM_NCPAINT.
WNDCLASSEX will not help here.

dv4-fa,

Those constants are just references into system-wide colors' scheme (pseudo-brushes' handles actually). You may use SetSysColors() if you're brave enough.