Hi,
currently there is no in-build setting for this, but you could create a
useraction which calls Krusader's dbus interface to open a new tab.
With 'qdbus' for example you could run: "qdbus
org.krusader /Instances/krusader/left_manager
org.krusader.PanelManager.newTab /raid"
Or: "qdbus org.krusader /Instances/krusader
org.krusader.Instance.openUrl /raid"
Jan