=== modified file 'common/zoom.cpp'
--- old/common/zoom.cpp	2012-01-23 04:33:36 +0000
+++ new/common/zoom.cpp	2012-03-22 17:42:49 +0000
@@ -81,24 +81,36 @@
     bool         zoom_at_cursor = false;
     BASE_SCREEN* screen = GetScreen();
     wxPoint      center = screen->GetScrollCenterPosition();
+    wxPoint      MousePosition = screen->RefPos(true); // get the mouse position where the zoom command was issued
+    double       magn_factor = screen->GetZoom(); // get the current zoom factor to calculate the magnification factor later on.
+    wxPoint      canvascenter = m_canvas->GetScreenCenterLogicalPosition();  // the center of the currently seen section of the drawing area
 
     switch( id )
     {
     case ID_POPUP_ZOOM_IN:
-        zoom_at_cursor = true;
-        center = screen->GetCrossHairPosition();
+        if( screen->SetPreviousZoom() )
+        {
+            magn_factor /= screen->GetZoom(); // calculate the relative magnification between the previous and the new zoom factor
+            // The center for redrawing the screen is somewhere on a line inbetween canvascenter and MousePosition. Where exactly is determined by the magnification factor.
+            center = wxPoint(wxRound((canvascenter.x-MousePosition.x)/magn_factor+MousePosition.x),wxRound((canvascenter.y-MousePosition.y)/magn_factor+MousePosition.y));
+            RedrawScreen( center, zoom_at_cursor );
+        }
+        break;
 
-    // fall thru
     case ID_ZOOM_IN:
         if( screen->SetPreviousZoom() )
             RedrawScreen( center, zoom_at_cursor );
         break;
 
     case ID_POPUP_ZOOM_OUT:
-        zoom_at_cursor = true;
-        center = screen->GetCrossHairPosition();
+        if( screen->SetNextZoom() )
+        {
+            magn_factor /= screen->GetZoom();
+            center = wxPoint(wxRound((canvascenter.x-MousePosition.x)/magn_factor+MousePosition.x),wxRound((canvascenter.y-MousePosition.y)/magn_factor+MousePosition.y));
+            RedrawScreen( center, zoom_at_cursor );
+        }
+        break;
 
-    // fall thru
     case ID_ZOOM_OUT:
         if( screen->SetNextZoom() )
             RedrawScreen( center, zoom_at_cursor );