diff --git a/buffer.py b/buffer.py
index e6e242e..06418ef 100644
--- a/buffer.py
+++ b/buffer.py
@@ -523,6 +523,10 @@ class Binary32Buffer(FileBuffer):
     def __init__(self, path, nl='\n', name=None):
         '''fb = FileBuffer(path)'''
         FileBuffer.__init__(self, path, nl, name)
+    def overwrite_char(self, p, c, act=ACT_NORM, force=False):
+        Buffer.overwrite_char(self, p, c, act, force)
+        rawline = self.rawdata[p.y]
+        self.rawdata[p.y] = rawline[0:p.x] + c + rawline[p.x + 1:]
     def read_filter(self, data):
         self.rawdata = []
         lines = []
diff --git a/window.py b/window.py
index 269260f..904f4d0 100644
--- a/window.py
+++ b/window.py
@@ -541,7 +541,7 @@ class Window(object):
     def overwrite_char(self, p, c):
         line = self.buffer.lines[p.y]
         if p.x >= len(line):
-            self.insert_string(p, c)
+            return
         elif p.x == len(line) - 1:
             self.buffer.overwrite_char(p, c)
             if p.y < len(self.buffer.lines):