diff --git a/application.py b/application.py
index 9fff1f3..e715aff 100755
--- a/application.py
+++ b/application.py
@@ -625,8 +625,8 @@ class Application(object):
                             self.highlight_chars(slot.y_offset + count, px-x + w.mode.lmargin, p2.x-x, fg, bg)
                             break
                         else:
-                            self.highlight_chars(slot.y_offset + count, px-x + w.mode.lmargin, slot.width, fg, bg)
-                            px += slot.width - px + x
+                            self.highlight_chars(slot.y_offset + count, px-x + w.mode.lmargin, slot.width - 1, fg, bg)
+                            px += slot.width - px + x - 1
                     if x + slot.width >= len(w.buffer.lines[y]):
                         x = 0
                         y += 1
diff --git a/bufferlist.py b/bufferlist.py
index 239e00f..9857117 100644
--- a/bufferlist.py
+++ b/bufferlist.py
@@ -27,6 +27,7 @@ class Slot(object):
             return None
 
 class VSlot(Slot):
+    size    = 0
     slots   = []
     heights = []
     def __init__(self, height, width, y_offset=0, x_offset=0):
@@ -45,24 +46,67 @@ class VSlot(Slot):
         self.y_offset = y_offset
         self.x_offset = x_offset
         percs = self.get_percs()
-        heights = [int(self.height * p) for p in percs]
-        assert sum(heights) <= self.height
+        self.heights = [int(self.height * p) for p in percs]
+        assert sum(self.heights) <= self.height
         i = 0
-        while sum(heights) < self.height:
-            heights[i] += 1
+        while sum(self.heights) < self.height:
+            self.heights[i] += 1
             i = (i + 1) % self.height
             self.window.set_size(self.width, self.height)
         total = 0
-        for i in range(0, heights):
+        for i in range(0, self.size):
             if self.slots[i] is not None:
-                (slot, height) = (self.slots[i], heights[i])
+                (slot, height) = (self.slots[i], self.heights[i])
                 slot.resize(height, width, y_offset + total, x_offset)
                 total += height
-    def set(self, w):
+
+    def add_slot(self):
+        self.size += 1
+        self.slots.append(Slot(self.height, self.width, 0))
+        self.heights.append(0)
+        self.fit_slots()
+        return len(self.slots) - 1
+    def empty_slot(self, i):
+        assert i > -1 and i < len(self.slots), "slot %d does not exist" % i
+        return self.slots[i].is_empty()
+    def unset_slot(self, i):
+        assert i > -1 and i < len(self.slots), "slot %d does not exist" % i
+        old_w = self.slots[i].unset()
+        if old_w is not None:
+            old_b = old_w.buffer
+            if not self.is_buffer_visible(old_b):
+                self.hidden_buffers.insert(0, old_b)
+            if len(old_b.windows) > 1:
+                old_b.remove_window(old_w)
+
+    def set_slot(self, i, b):
+        assert i > -1 and i < len(self.slots), "slot %d does not exist" % i
+        assert b in self.buffers, "buffer %s does not exist" % (b.name())
+        slot = self.slots[i]
+        self.unset_slot(i)
+
+        if b in self.hidden_buffers:
+            self.hidden_buffers.remove(b)
+        if self.is_window_visible(b.windows[0]):
+            app = b.windows[0].application
+            w = window.Window(b, app, height=slot.height, width=slot.width)
+        else:
+            w = b.windows[0]
+        slot.set(w)
+
+    def remove_slot(self, i):
+        assert i > -1 and i < len(self.slots), "slot %d does not exist" % i
+        self.unset_slot(i)
+        del self.slots[i]
+        self.fit_slots()
+
+
+
+    def set(self, i, w):
         self.window  = w
         self.resize(self.height, self.width, self.y_offset, self.x_offset)
         w.set_size(self.width, self.height)
-    def unset(self):
+    def unset(self, i):
         if not self.is_empty():
             old_w = self.window
             self.window = None