diff --git a/Makefile b/Makefile
index ac6fbdbf..d5faff06 100644
--- a/Makefile
+++ b/Makefile
@@ -97,5 +97,5 @@ test: .venv
 	flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics --exclude .venv,build,tmp ; \
 	pytest tests/pytest/test_003_string.py ; \
 	pytest tests/pytest/test_002_textedit.py ; \
-	pytest tests/pytest/test_001_demo.py ;
+	pytest -v tests/pytest/test_001_demo.py ;
 
diff --git a/TermTk/TTkCore/canvas.py b/TermTk/TTkCore/canvas.py
index 3896eaf6..a0b45667 100644
--- a/TermTk/TTkCore/canvas.py
+++ b/TermTk/TTkCore/canvas.py
@@ -192,10 +192,10 @@ class TTkCanvas:
             else:
                 self._colors[y][x+i] =  colors[i].mod(x+i,y)
         # Check the full wide chars on the edge of the two canvasses
-        if 0 <= (x+a) < self._width and self._data[y][x+a] == '':
+        if ((0 <= (x+a) < self._width) and self._data[y][x+a] == ''):
             self._data[y][x+a]   = TTkCfg.theme.unicodeWideOverflowCh[0]
             self._colors[y][x+a] = TTkCfg.theme.unicodeWideOverflowColor
-        if 0 <= (x+b-1) < self._width and TTkString._isWideCharData(self._data[y][x+b-1]):
+        if ((0 <= (x+b-1) < self._width) and TTkString._isWideCharData(self._data[y][x+b-1])):
             self._data[y][x+b-1]   = TTkCfg.theme.unicodeWideOverflowCh[1]
             self._colors[y][x+b-1] = TTkCfg.theme.unicodeWideOverflowColor
 
@@ -598,15 +598,10 @@ class TTkCanvas:
         w = min(w,self._width-x)
         h = min(h,self._height-y)
 
-        # if x>=self._width:    x=self._width-1
-        # if y>=self._height:   y=self._height-1
-        # if w>=self._width-x:  w=self._width-x
-        # if h>=self._height-y: h=self._height-y
-
-        xoffset = 0 if x>=bx else bx-x
-        yoffset = 0 if y>=by else by-y
-        wslice = w if x+w < bx+bw else bx+bw-x
-        hslice = h if y+h < by+bh else by+bh-y
+        xoffset = min(max(0,bx-x),canvas._width-1)
+        yoffset = min(max(0,by-y),canvas._height-1)
+        wslice = min(w if x+w < bx+bw else bx+bw-x,canvas._width)
+        hslice = min(h if y+h < by+bh else by+bh-y,canvas._height)
 
         for iy in range(yoffset,hslice):
             a, b = x+xoffset, x+wslice
@@ -614,16 +609,16 @@ class TTkCanvas:
             self._colors[y+iy][a:b] = canvas._colors[iy][xoffset:wslice]
 
             # Check the full wide chars on the edge of the two canvasses
-            if 0 <= a < self._width and self._data[y+iy][a]=='':
+            if ((0 <= a < self._width) and self._data[y+iy][a]==''):
                 self._data[y+iy][a]   = TTkCfg.theme.unicodeWideOverflowCh[0]
                 self._colors[y+iy][a] = TTkCfg.theme.unicodeWideOverflowColor
-            if 0 < b <= self._width and TTkString._isWideCharData(self._data[y+iy][b-1]):
+            if ((0 < b <= self._width) and TTkString._isWideCharData(self._data[y+iy][b-1])):
                 self._data[y+iy][b-1]   = TTkCfg.theme.unicodeWideOverflowCh[1]
                 self._colors[y+iy][b-1] = TTkCfg.theme.unicodeWideOverflowColor
-            if 0 < a <= self._width and TTkString._isWideCharData(self._data[y+iy][a-1]):
+            if ((0 < a <= self._width) and TTkString._isWideCharData(self._data[y+iy][a-1])):
                 self._data[y+iy][a-1]   = TTkCfg.theme.unicodeWideOverflowCh[1]
                 self._colors[y+iy][a-1] = TTkCfg.theme.unicodeWideOverflowColor
-            if 0 <= b < self._width and self._data[y+iy][b]=='':
+            if ((0 <= b < self._width) and self._data[y+iy][b]==''):
                 self._data[y+iy][b]   = TTkCfg.theme.unicodeWideOverflowCh[0]
                 self._colors[y+iy][b] = TTkCfg.theme.unicodeWideOverflowColor
 
diff --git a/tests/pytest/test_001_demo.py b/tests/pytest/test_001_demo.py
index d5428f06..37b99768 100755
--- a/tests/pytest/test_001_demo.py
+++ b/tests/pytest/test_001_demo.py
@@ -153,7 +153,18 @@ def test_demo():
     assert demo.demoShowcase(root) != None
     root.quit()
 
+def message_handler(mode, context, message):
+    msgType = "NONE"
+    if   mode == demo.ttk.TTkLog.InfoMsg:     msgType = "[INFO]"
+    elif mode == demo.ttk.TTkLog.WarningMsg:  msgType = "[WARNING]"
+    elif mode == demo.ttk.TTkLog.CriticalMsg: msgType = "[CRITICAL]"
+    elif mode == demo.ttk.TTkLog.FatalMsg:    msgType = "[FATAL]"
+    elif mode == demo.ttk.TTkLog.ErrorMsg:    msgType = "[ERROR]"
+    print(f"{msgType} {context.file} {message}")
+
 def test_recording1():
+    # demo.ttk.TTkLog.use_default_file_logging()
+    demo.ttk.TTkLog.installMessageHandler(message_handler)
     root = TTkRecord(title="pyTermTk Demo Record", record=False)
     root.loadQueue(open('tmp/test.input.bin', 'rb'))
     winTabbed1 = demo.ttk.TTkWindow(parent=root,pos=(0,0), size=(80,24), title="pyTermTk Showcase", border=True, layout=demo.ttk.TTkGridLayout())