diff --git a/libgui/GuiWindow.py b/libgui/GuiWindow.py
index 91fb6b6..48c1dc0 100644
--- a/libgui/GuiWindow.py
+++ b/libgui/GuiWindow.py
@@ -9,12 +9,13 @@ import wx
 class GuiWindow(wx.ScrolledWindow):
     # {{{ _updateScrollBars(self)
     def _updateScrollBars(self):
-        clientSize = self.GetClientSize()
-        if (self.size[0] > clientSize[0]) or (self.size[1] > clientSize[1]):
-            self.scrollFlag = True; super().SetVirtualSize(self.size);
-        elif self.scrollFlag    \
-        and  ((self.size[0] <= clientSize[0]) or (self.size[1] <= clientSize[1])):
-            self.scrollFlag = False; super().SetVirtualSize((0, 0));
+        if self.size != None:
+            clientSize = self.GetClientSize()
+            if (self.size[0] > clientSize[0]) or (self.size[1] > clientSize[1]):
+                self.scrollFlag = True; super().SetVirtualSize(self.size);
+            elif self.scrollFlag    \
+            and  ((self.size[0] <= clientSize[0]) or (self.size[1] <= clientSize[1])):
+                self.scrollFlag = False; super().SetVirtualSize((0, 0));
     # }}}
 
     # {{{ onClose(self, event)
@@ -59,10 +60,10 @@ class GuiWindow(wx.ScrolledWindow):
     # }}}
 
     #
-    # __init__(self, parent, pos, scrollStep, size, style=0): initialisation method
-    def __init__(self, parent, pos, scrollStep, size, style=0):
-        super().__init__(parent, pos=pos, size=size, style=style)
-        self.pos, self.scrollFlag, self.scrollStep, self.size = pos, False, scrollStep, size
+    # __init__(self, parent, pos, scrollStep, style=0): initialisation method
+    def __init__(self, parent, pos, scrollStep, style=0):
+        super().__init__(parent, pos=pos, style=style) if style != 0 else super().__init__(parent, pos=pos)
+        self.pos, self.scrollFlag, self.scrollStep, self.size = pos, False, scrollStep, None
         for eventType, f in (
                 (wx.EVT_CHAR, self.onKeyboardInput), (wx.EVT_CLOSE, self.onClose), (wx.EVT_ENTER_WINDOW, self.onEnterWindow),
                 (wx.EVT_LEAVE_WINDOW, self.onLeaveWindow), (wx.EVT_LEFT_DOWN, self.onMouseInput), (wx.EVT_MOTION, self.onMouseInput),
diff --git a/libroar/RoarAssetsWindow.py b/libroar/RoarAssetsWindow.py
index 5ab70fe..675d6e7 100644
--- a/libroar/RoarAssetsWindow.py
+++ b/libroar/RoarAssetsWindow.py
@@ -88,10 +88,16 @@ class RoarAssetsWindow(GuiMiniFrame):
     # {{{ _updateScrollBars(self)
     def _updateScrollBars(self):
         clientSize = self.panelCanvas.GetClientSize()
-        if (self.panelCanvas.size[0] > clientSize[0]) or (self.panelCanvas.size[1] > clientSize[1]):
-            self.scrollFlag = True; super(wx.ScrolledWindow, self.panelCanvas).SetVirtualSize(self.panelCanvas.size);
+        if self.currentIndex != None:
+            panelSize = [a * b for a, b in zip(self.canvasList[self.currentIndex][0].size, self.backend.cellSize)]
+        elif self.panelCanvas.size != None:
+            panelSize = list(self.panelCanvas.size)
+        else:
+            return
+        if (panelSize[0] > clientSize[0]) or (panelSize[1] > clientSize[1]):
+            self.scrollFlag = True; super(wx.ScrolledWindow, self.panelCanvas).SetVirtualSize(panelSize);
         elif self.scrollFlag    \
-        and  ((self.panelCanvas.size[0] <= clientSize[0]) or (self.panelCanvas.size[1] <= clientSize[1])):
+        and  ((panelSize[0] <= clientSize[0]) or (panelSize[1] <= clientSize[1])):
             self.scrollFlag = False; super(wx.ScrolledWindow, self.panelCanvas).SetVirtualSize((0, 0));
     # }}}
 
@@ -324,15 +330,16 @@ class RoarAssetsWindow(GuiMiniFrame):
         self.listView.Bind(wx.EVT_LIST_ITEM_SELECTED, self.onListViewItemSelected)
         self.listView.Bind(wx.EVT_RIGHT_DOWN, self.onListViewRightDown)
 
-        self.panelCanvas = GuiWindow(self, (0, 0), cellSize, (int(size[0] / 2), int(size[1] / 2)), wx.BORDER_SUNKEN)
+        self.panelCanvas = GuiWindow(self, (0, 0), cellSize, wx.BORDER_SUNKEN)
         self.panelCanvas.Bind(wx.EVT_LEFT_DOWN, self.onPanelLeftDown)
         self.panelCanvas.Bind(wx.EVT_PAINT, self.onPanelPaint)
         self.panelCanvas.Bind(wx.EVT_SIZE, self.onPanelSize)
-        self._updateScrollBars()
 
         self.sizer = wx.BoxSizer(wx.VERTICAL)
         self.sizer.AddMany(((self.listView, 0, wx.ALL | wx.EXPAND, 4), (self.panelCanvas, 1, wx.ALL | wx.EXPAND, 4),))
+        self.panelCanvas.SetMinSize((int(size[0] / 2), int(size[1] / 2)))
         self.SetSizerAndFit(self.sizer)
+        self._updateScrollBars()
         self.Show(True)
 
 # vim:expandtab foldmethod=marker sw=4 ts=4 tw=120
diff --git a/libroar/RoarCanvasWindow.py b/libroar/RoarCanvasWindow.py
index c6ee63d..c3dff64 100644
--- a/libroar/RoarCanvasWindow.py
+++ b/libroar/RoarCanvasWindow.py
@@ -201,7 +201,8 @@ class RoarCanvasWindow(GuiWindow):
     #
     # __init__(self, backend, canvas, cellSize, commands, parent, parentFrame, pos, scrollStep, size): initialisation method
     def __init__(self, backend, canvas, cellSize, commands, parent, parentFrame, pos, scrollStep, size):
-        super().__init__(parent, pos, scrollStep, [w * h for w, h in zip(cellSize, size)])
+        super().__init__(parent, pos, scrollStep)
+        self.size = size
         self.backend, self.canvas, self.cellSize, self.commands, self.parentFrame = backend(self.size, cellSize), canvas, cellSize, commands(self, parentFrame), parentFrame
         self.brushColours, self.brushPos, self.brushSize, self.dirty, self.lastCellState = [4, 1], [0, 0], [1, 1], False, None
         self.popupEventDc = None