Instead of storing a Command* we can store the command ID, which it's
less problematic in extreme cases where the Command that is being
referenced is deleted or recreated, i.e. when a plugin is
disabled/re-enabled.
This is a problem introduced with the plugin groups, but now we use a
group to store the list of recent files. With this commit we fixed
some bugs in the impl of menu groups.
David Capello
lampysprites