sshmenu freezes when dropping an item onto itself. This has been reported in the Ubuntu bug tracker and a patch has been provided. Check
for reference, reproduction and a patch.
Thank you for providing sshmenu.
I haven't been able to make the drag-n-drop work without triggering this problem so in release 3.16 I've simply disabled the feature (as per my patch on the Ubuntu bug report)
This issue seems to be fixed in version 0.19 of the Ruby-GTK bindings. Version 3.17 of SSHMenu now enables drag-n-drop if it detects that the Ruby-GTK bindings are version 0.19 or better.