1. I want to look at the source of the function XCreateSimpleWindow(). I extracted the xserver sources and greped it - but I could not find it Where are the sources of Xlib function calls located ? 2. When I create a window using XCreateSimpleWindow() function - the window has the decoration of the Ubuntu desktop that I am using. I was informed that window manager captures it and re-parents the current window to a new window with the title bar as one window and the current window as another. So how that happen ? How does the window manager know that I have created a window using the raw X command ? (maybe I assume a event is sent) . I just want to confirm ! 3. There are two structures : Display, Screen. How does the window manager implement the Virtual Desktops ? Is there any other structure like a VirtualScreen, Viewport ?? 4. What is the actual role of X server ? Most of the work is done by window manager and other libraries. What I have been able to gather is : - It creates and manages windows - Handles the input events - Informs when the window needs to be redrawn. Am I right or I left something. Most of the documentation on the net is old and has no information about current releases. I am trying to understand the X server - so the many questions that I could not find answers anywhere. ------------