eeschema: bug soved (see changelog). Doc update

change_log.txt

@@ -5,6 +5,12 @@ Started 2007-June-11
 Please add newer entries at the top, list the date and your name with
 email address.
 
+2008-June-15 UPDATE   Jean-Pierre Charras <jean-pierre.charras@inpg.fr>
+================================================================================
++eeschema:
+    Bug solved: Eeschema crashed when creating a new subsheet with the same
+    filename as an existing filename, if loading this existing file.
+
 
 2008-June-11 UPDATE   Jean-Pierre Charras <jean-pierre.charras@inpg.fr>
 ================================================================================

eeschema/class_drawsheet.cpp

@@ -574,12 +574,15 @@ bool DrawSheetStruct::ChangeFileName( WinEDA_SchematicFrame* aFrame, const wxStr
         if( IsOK( NULL, msg ) )
         {
             LoadFromFile = true;
+            if ( m_AssociatedScreen )   // Can be NULL if loading a file when creating a new sheet
+            {
                 m_AssociatedScreen->m_RefCount--;                 //be careful with these
                 if( m_AssociatedScreen->m_RefCount == 0 )
                     SAFE_DELETE( m_AssociatedScreen );
                 m_AssociatedScreen = NULL;         //will be created later
             }
         }
+    }
 
     // if an associated screen exists, shared between this sheet and others sheets, what we do ?
     if( m_AssociatedScreen && ( m_AssociatedScreen->m_RefCount > 1 ) )