Menu is unusable once a error occured while loading its data
Since 61900bf04dfb error occurring while loading a tree view result in #ERROR label being displayed everywhere. In my case, it happened while I was opening a submenu, it made the submenu completely useless.
In a normal O2M, it's not an issue as we can always reload the record. But the fix for #2011 (closed) removed the shortcut that allows to reload the menu (I did it but I don't remember the rational behind it, probably because it was seldomly used and was interfering with the native CTRL-T of browsers).
I wonder if we shouldn't add it back (CTRL-M maybe) as now an error while loading the menu will make it useless (before it was silently ignored) both on sao and tryton.