diff --git a/c/xlib/window.c b/c/xlib/window.c
index 88786c8..e13efc4 100644
--- a/c/xlib/window.c
+++ b/c/xlib/window.c
@@ -131,9 +131,10 @@ s48_value scx_Get_Window_Attributes(s48_value Xdisplay, s48_value Xwindow) {
     //S48_VECTOR_SET(res, 22, s48_enter_fixnum((long)WA.screen));
     // WA.screen not yet supported
     res = s48_cons(s48_enter_integer((1L<<23) - 1), res);
+
+    S48_GC_UNPROTECT();
   }
 
-  S48_GC_UNPROTECT();
   return res;
 }
 
@@ -150,7 +151,7 @@ s48_value Changes_To_XWindowChanges(s48_value changes, XWindowChanges* WC) {
   if (mask & CWHeight)
     WC->height = s48_extract_integer(S48_VECTOR_REF(v, 3));
   if (mask & CWBorderWidth)
-    WC->height = s48_extract_integer(S48_VECTOR_REF(v, 4));
+    WC->border_width = s48_extract_integer(S48_VECTOR_REF(v, 4));
   if (mask & CWSibling)
     WC->sibling = SCX_EXTRACT_WINDOW(S48_VECTOR_REF(v, 5));
   if (mask & CWStackMode)
@@ -211,8 +212,10 @@ s48_value scx_Query_Tree (s48_value Xwindow, s48_value Xdisplay) {
   s48_value v = S48_FALSE, ret = S48_FALSE;
   S48_DECLARE_GC_PROTECT(2);
   
-  XQueryTree (SCX_EXTRACT_DISPLAY(Xdisplay), SCX_EXTRACT_WINDOW(Xwindow), 
-	      &root, &parent, &children, &n);
+  if (! XQueryTree (SCX_EXTRACT_DISPLAY(Xdisplay),
+		    SCX_EXTRACT_WINDOW(Xwindow), 
+		    &root, &parent, &children, &n))
+    return S48_FALSE;
 
   ret = s48_make_vector(3, S48_FALSE);
   v = S48_FALSE;
@@ -224,11 +227,13 @@ s48_value scx_Query_Tree (s48_value Xwindow, s48_value Xdisplay) {
   for (i = 0; i < n; i++) {
     S48_VECTOR_SET(v, i, SCX_ENTER_WINDOW(children[i]));
   }
+  if (children != NULL) XFree(children);
 
   S48_VECTOR_SET(ret, 0, SCX_ENTER_WINDOW(root));
   S48_VECTOR_SET(ret, 1, SCX_ENTER_WINDOW(parent));
   S48_VECTOR_SET(ret, 2, v);
 
+
   S48_GC_UNPROTECT();
   return ret;
 }