#3822 copy window depth and visual from parent window

which is the root window.
We don't hardcode 24 bit depth because it should be possible to run the seamless server against a 16-bit display

xpra/x11/bindings/window_bindings.pyx

@@ -62,6 +62,8 @@ cdef extern from "X11/Xlib.h":
     int SelectionNotify
     int ConfigureNotify
 
+    int CopyFromParent
+
     int CWEventMask
     int CWColormap
     int CWBorderWidth
@@ -883,26 +885,26 @@ cdef class X11WindowBindingsInstance(X11CoreBindingsInstance):
         self.context_check("CreateCorralWindow")
         #copy most attributes from the window we will wrap:
         cdef int ox, oy
-        cdef Window root_return
+        cdef Window root
         cdef unsigned int width, height, border_width, depth
-        if not XGetGeometry(self.display, xid, &root_return,
+        if not XGetGeometry(self.display, xid, &root,
                         &ox, &oy, &width, &height, &border_width, &depth):
             return None
-        cdef XWindowAttributes attrs
-        cdef Status status = XGetWindowAttributes(self.display, xid, &attrs)
-        if status==0:
-            return None
         cdef XSetWindowAttributes attributes
         memset(<void*> &attributes, 0, sizeof(XSetWindowAttributes))
         # We enable PropertyChangeMask so that we can call
         # get_server_time on this window.
         attributes.event_mask = PropertyChangeMask | StructureNotifyMask | SubstructureNotifyMask
-        attributes.colormap = attrs.colormap
-        cdef Visual *visual = attrs.visual
-        cdef unsigned long valuemask = CWEventMask | CWColormap
+        #get depth from parent window:
+        cdef int px, py
+        cdef unsigned int pw, ph, pborder, pdepth
+        if not XGetGeometry(self.display, parent, &root,
+                        &px, &py, &pw, &ph, &pborder, &pdepth):
+            return None
+        cdef unsigned long valuemask = CWEventMask
         cdef Window window = XCreateWindow(self.display, parent,
-                                           x, y, width, height, border_width, depth,
-                                           InputOutput, visual,
+                                           x, y, width, height, 0, pdepth,
+                                           InputOutput, <Visual*> CopyFromParent,
                                            valuemask, &attributes)
         return window