Integrated Boux's fixes for Win32 + ATI graphics configurations:

- Fixed invisible context menu in fullscreen mode
- Fixed menu bar overlapping top of 3D view

src/celestia/win32/winmain.cpp

@@ -1972,7 +1972,7 @@ HWND CreateOpenGLWindow(int x, int y, int width, int height,
     DWORD dwStyle;
     if (newMode != 0)
     {
-        dwStyle = WS_POPUP;
+        dwStyle = WS_POPUPWINDOW | WS_MAXIMIZE;
     }
     else
     {
@@ -2006,6 +2006,11 @@ HWND CreateOpenGLWindow(int x, int y, int width, int height,
 		return NULL;
     }
 
+    if (newMode == 0)
+        SetMenu(hwnd, menuBar);
+    else
+        hideMenuBar = true;
+
 	bool firstContext = false;
     if (glContext == NULL)
 	{
@@ -2025,11 +2030,6 @@ HWND CreateOpenGLWindow(int x, int y, int width, int height,
 		}
 	}
 
-    if (newMode == 0)
-        SetMenu(hwnd, menuBar);
-    else
-        hideMenuBar = true;
-
     return hwnd;
 }