因为他们是兄弟窗口嘛MSDN里说的很清楚 GW_HWNDNEXT The retrieved handle identifies the window below the specified window in the z-order. If the specified window is a topmost window, the handle identifies the topmost window below the specified window. If the specified window is a child window, the handle identifies the sibling window below the specified window. 如果指定窗口是子窗口,则返回兄弟窗口
GW_HWNDNEXT
The retrieved handle identifies the window below the specified window in the z-order. If the specified window is a topmost window, the handle identifies the topmost window below the specified window. If the specified window is a child window, the handle identifies the sibling window below the specified window.
如果指定窗口是子窗口,则返回兄弟窗口