diff --git a/detailview.c b/detailview.c
index 49630b5327b0b7ad9df3458a5c817db2e1c1ec63..edc6ce74634d0b2ed41aedfdb457be7415604f73 100755
--- a/detailview.c
+++ b/detailview.c
@@ -2011,13 +2011,17 @@ static void onSizeAllocateDetailView(GtkWidget *detailView, GtkAllocation *alloc
    * window size changes. Find its new width and cache it. All trees should resize
    * in the same manner, so their columns should be the same size. */
   GtkWidget *tree = detailViewGetFirstTree(detailView);
-  GtkTreeViewColumn *column = gtk_tree_view_get_column(GTK_TREE_VIEW(tree), BLXCOL_SEQUENCE);
+  
+  if (tree && GTK_WIDGET_VISIBLE(tree))
+    {
+      GtkTreeViewColumn *column = gtk_tree_view_get_column(GTK_TREE_VIEW(tree), BLXCOL_SEQUENCE);
 
-  DetailViewColumnInfo *columnInfo = detailViewGetColumnInfo(detailView, BLXCOL_SEQUENCE);
-  columnInfo->width = gtk_tree_view_column_get_width(column);
-      
-  /* Perform updates required on the sequence col after its size has changed */
-  updateSeqColumnSize(detailView);
+      DetailViewColumnInfo *columnInfo = detailViewGetColumnInfo(detailView, BLXCOL_SEQUENCE);
+      columnInfo->width = gtk_tree_view_column_get_width(column);
+          
+      /* Perform updates required on the sequence col after its size has changed */
+      updateSeqColumnSize(detailView);
+    }
 }
 
 
diff --git a/detailviewtree.c b/detailviewtree.c
index fcbb0684abc03d792365883c0a8ef2e108582a90..d0a01969e8cf532eff6d95dec7afdf3473229d08 100755
--- a/detailviewtree.c
+++ b/detailviewtree.c
@@ -1635,7 +1635,7 @@ static void cellDataFunctionNameCol(GtkTreeViewColumn *column,
   /* Get the MSP(s) for this row. They should all have the same sequence name. */
   GList	*mspGList = treeGetMsps(model, iter);
 
-  if (g_list_length(mspGList) > 0)
+  if (GTK_WIDGET_VISIBLE(tree) && g_list_length(mspGList) > 0)
     {
       MSP *msp = (MSP*)(mspGList->data);