grahamcamelia
I don't know what's the big difference between calling the same script in the Python Shell and on another place (Tool in Shelf, python node, etc.).
The main difference is that the Python Shell runs in a separate thread where as things like shelf tools, menu entries, etc are run in the main thread. A lot of things definitely can cause weird behavior/crashes when running from the shell (think Qt) so if you're doing something complex it'a always advised to do it via shelf tool or menu item.
We've been successfully using the hou.Node methods for quite a while without running into issues so it could be very specific to what you are attempting to copy.
Thank you Graham for your answer. You confirm what I thought.
Yes, one day I had this same weird behavior with a tool I did in Qt (events log when I move the cursor). On the Houdini documentation, there is a warning about that here [www.sidefx.com] but I thought it was just about UI. So now, I will only use the Python Shell for simple needs.