How to change window style for hwnd ?

[BestWarrior]

It is possible to change the style without editing the source code like here:

Transparent window

This works: const auto hwnd = GetActiveWindow(); if (hwnd) { SetWindowLongPtr(hwnd, GWL_STYLE, WS_VISIBLE); SetWindowLongPtr(hwnd, GWL_EXSTYLE, WS_EX_LAYERED | WS_EX_TRANSPARENT); RECT rect; GetWindowRect(hwnd, &rect); SetWindowPos(hwnd, HWND_TOPMOST, rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top, SWP_SHOWWINDOW); const MARGINS margins{ -1 }; DwmExtendFrameIntoClientArea(hwnd, &margins); } R…

The problem is that SetLayeredWindowAttributes works only with LWA_ALPHA, not with LWA_COLORKEY.