diff --git a/common/utils/T/tracer/gui/gui.c b/common/utils/T/tracer/gui/gui.c
index 2166774d929f441595ca06d6fa080a2980324c12..ef8640b0def445e5cc4d29f13965d981f3bd3dd3 100644
--- a/common/utils/T/tracer/gui/gui.c
+++ b/common/utils/T/tracer/gui/gui.c
@@ -9,18 +9,24 @@ void glock(gui *_gui)
 {
   struct gui *g = _gui;
   if (pthread_mutex_lock(g->lock)) ERR("mutex error\n");
-  xlock(g->x);
 }
 
 void gunlock(gui *_gui)
 {
   struct gui *g = _gui;
-  xunlock(g->x);
   if (pthread_mutex_unlock(g->lock)) ERR("mutex error\n");
 }
 
 int new_color(gui *_gui, char *color)
 {
   struct gui *g = _gui;
-  return x_new_color(g->x, color);
+  int ret;
+
+  glock(g);
+
+  ret = x_new_color(g->x, color);
+
+  gunlock(g);
+
+  return ret;
 }
diff --git a/common/utils/T/tracer/gui/init.c b/common/utils/T/tracer/gui/init.c
index 445f696643c0eba3c4ef6ac18e72fa26cb8889dd..c6d5e3e435366b574b3495ee41b9c6df45621744 100644
--- a/common/utils/T/tracer/gui/init.c
+++ b/common/utils/T/tracer/gui/init.c
@@ -12,8 +12,6 @@ gui *gui_init(void)
 {
   struct gui *ret;
 
-  x_init_threading();
-
   ret = calloc(1, sizeof(struct gui));
   if (ret == NULL) OOM;
 
@@ -25,7 +23,12 @@ gui *gui_init(void)
   if (pipe(ret->event_pipe))
     ERR("%s\n", strerror(errno));
 
+  /* lock not necessary but there for consistency (when instrumenting x.c
+   * we need the gui to be locked when calling any function in x.c)
+   */
+  glock(ret);
   ret->x = x_open();
+  gunlock(ret);
 
   return ret;
 }
diff --git a/common/utils/T/tracer/gui/loop.c b/common/utils/T/tracer/gui/loop.c
index 94b7fe54bd5f1cc436f8d05ebc7f6e51f639c464..8ceb3c06e1c4936dc508fea8e1ce8dc33b0d99c3 100644
--- a/common/utils/T/tracer/gui/loop.c
+++ b/common/utils/T/tracer/gui/loop.c
@@ -16,14 +16,21 @@ void gui_loop(gui *_gui)
   int maxfd;
   fd_set rd;
 
+  /* lock not necessary but there for consistency (when instrumenting x.c
+   * we need the gui to be locked when calling any function in x.c)
+   */
+  glock(g);
   xfd = x_connection_fd(g->x);
+  gunlock(g);
   eventfd = g->event_pipe[0];
 
   if (eventfd > xfd) maxfd = eventfd;
   else               maxfd = xfd;
 
   while (1) {
+    glock(g);
     x_flush(g->x);
+    gunlock(g);
     FD_ZERO(&rd);
     FD_SET(xfd, &rd);
     FD_SET(eventfd, &rd);
diff --git a/common/utils/T/tracer/gui/x.c b/common/utils/T/tracer/gui/x.c
index 12888da468986fa52c292d9626c09799c97bff1f..50164dce359a570a2df901b5e1c3dac46bb8dae6 100644
--- a/common/utils/T/tracer/gui/x.c
+++ b/common/utils/T/tracer/gui/x.c
@@ -6,23 +6,6 @@
 #include <stdlib.h>
 #include <string.h>
 
-void x_init_threading(void)
-{
-  if (XInitThreads() == False) abort();
-}
-
-void xlock(x_connection *_x)
-{
-  struct x_connection *x = _x;
-  XLockDisplay(x->d);
-}
-
-void xunlock(x_connection *_x)
-{
-  struct x_connection *x = _x;
-  XUnlockDisplay(x->d);
-}
-
 int x_connection_fd(x_connection *_x)
 {
   struct x_connection *x = _x;
diff --git a/common/utils/T/tracer/gui/x.h b/common/utils/T/tracer/gui/x.h
index 82e46cac9da477c0159de80903877e87c21af7c6..c1f8d33d89e8831c8a1882ecbf737763c02191fb 100644
--- a/common/utils/T/tracer/gui/x.h
+++ b/common/utils/T/tracer/gui/x.h
@@ -6,11 +6,6 @@
 typedef void x_connection;
 typedef void x_window;
 
-void x_init_threading(void);
-
-void xlock(x_connection *x);
-void xunlock(x_connection *x);
-
 x_connection *x_open(void);
 
 x_window *x_create_window(x_connection *x, int width, int height,