diff --git a/tqdm/_tqdm.py b/tqdm/_tqdm.py
index 430ea9df..26a32d94 100755
--- a/tqdm/_tqdm.py
+++ b/tqdm/_tqdm.py
@@ -421,25 +421,27 @@ class tqdm(object):
         Remove from list and reposition other bars
         so that newer bars won't overlap previous bars
         """
-        try:  # in case instance was explicitly positioned, it won't be in set
-            with cls._lock:
+        with cls._lock:
+            try:
                 cls._instances.remove(instance)
+            except KeyError:
+                if not instance.gui:  # pragma: no cover
+                    raise
+            else:
                 for inst in cls._instances:
                     # negative `pos` means fixed
                     if inst.pos > abs(instance.pos):
                         inst.pos -= 1
                         # TODO: check this doesn't overwrite another fixed bar
-            # Kill monitor if no instances are left
-            if not cls._instances and cls.monitor:
-                try:
-                    cls.monitor.exit()
-                    del cls.monitor
-                except AttributeError:  # pragma: nocover
-                    pass
-                else:
-                    cls.monitor = None
-        except KeyError as e:
-            warn(str(e), TqdmWarning)
+        # Kill monitor if no instances are left
+        if not cls._instances and cls.monitor:
+            try:
+                cls.monitor.exit()
+                del cls.monitor
+            except AttributeError:  # pragma: nocover
+                pass
+            else:
+                cls.monitor = None
 
     @classmethod
     def write(cls, s, file=None, end="\n", nolock=False):
@@ -816,8 +818,6 @@ class tqdm(object):
         # not overwrite the outer progress bar
         if position is None:
             self.pos = self._get_free_pos(self)
-        elif position < 0:
-            raise ValueError("negative position")
         else:  # mark fixed positions as negative
             self.pos = -position
 
diff --git a/tqdm/tests/tests_tqdm.py b/tqdm/tests/tests_tqdm.py
index b132ac9e..89640d7f 100644
--- a/tqdm/tests/tests_tqdm.py
+++ b/tqdm/tests/tests_tqdm.py
@@ -989,8 +989,8 @@ def test_position():
     # Artificially test nested loop printing
     # Without leave
     our_file = StringIO()
-    t = tqdm(total=2, file=our_file, miniters=1, mininterval=0, maxinterval=0,
-             desc='pos2 bar', leave=False, position=2)
+    kwargs = dict(file=our_file, miniters=1, mininterval=0, maxinterval=0)
+    t = tqdm(total=2, desc='pos2 bar', leave=False, position=2, **kwargs)
     t.update()
     t.close()
     our_file.seek(0)
@@ -1006,12 +1006,10 @@ def test_position():
 
     # Test iteration-based tqdm positioning
     our_file = StringIO()
-    for _ in trange(2, file=our_file, miniters=1, mininterval=0, maxinterval=0,
-                    desc='pos0 bar', position=0):
-        for _ in trange(2, file=our_file, miniters=1, mininterval=0,
-                        maxinterval=0, desc='pos1 bar', position=1):
-            for _ in trange(2, file=our_file, miniters=1, mininterval=0,
-                            maxinterval=0, desc='pos2 bar', position=2):
+    kwargs["file"] = our_file
+    for _ in trange(2, desc='pos0 bar', position=0, **kwargs):
+        for _ in trange(2, desc='pos1 bar', position=1, **kwargs):
+            for _ in trange(2, desc='pos2 bar', position=2, **kwargs):
                 pass
     our_file.seek(0)
     out = our_file.read()
@@ -1044,12 +1042,11 @@ def test_position():
 
     # Test manual tqdm positioning
     our_file = StringIO()
-    t1 = tqdm(total=2, file=our_file, miniters=1, mininterval=0, maxinterval=0,
-              desc='pos0 bar', position=0)
-    t2 = tqdm(total=2, file=our_file, miniters=1, mininterval=0, maxinterval=0,
-              desc='pos1 bar', position=1)
-    t3 = tqdm(total=2, file=our_file, miniters=1, mininterval=0, maxinterval=0,
-              desc='pos2 bar', position=2)
+    kwargs["file"] = our_file
+    kwargs["total"] = 2
+    t1 = tqdm(desc='pos0 bar', position=0, **kwargs)
+    t2 = tqdm(desc='pos1 bar', position=1, **kwargs)
+    t3 = tqdm(desc='pos2 bar', position=2, **kwargs)
     for _ in _range(2):
         t1.update()
         t3.update()
@@ -1110,13 +1107,6 @@ def test_position():
         t3.close()
         t1.close()
 
-    try:
-        t = tqdm(total=1, file=our_file, position=-1)
-    except ValueError:
-        pass
-    else:
-        raise ValueError("expected negative positions to raise errors")
-
 
 @with_setup(pretest, posttest)
 def test_set_description():