gentoo-overlay/sci-biology/treeviewx/files/treeviewx-0.5.1-70_choose_tree.patch

## 70_choose_tree.dpatch by William Alexander Grant <william.grant@ubuntu.com.au>
--- tv-0.5.orig/tview.cpp
+++ tv-0.5/tview.cpp
@@ -209,7 +209,7 @@
         wxT("SVG vector picture files (*.svg)|*.svg"),
         wxSAVE|wxOVERWRITE_PROMPT);
 
-    if (dialog.ShowModal() == wxID_OK)
+    if ((dialog.ShowModal() == wxID_OK) && (p.GetNumTrees() != 0))
     {
 		wxSVGFileDC pictureDC (dialog.GetPath(), 600, 650) ;
 		OnDraw (&pictureDC);