Edge mode does not change when the user changes relationships

[oxy86]

This is a minor glitch but it should be noted:

Say you create a network with directed edges. Suppose you add another relationship and change the edge mode to undirected. Now, you have a network with 2 relations: a directed one and an undirected one. If you change back to the original relationship (Alt+Left arrow), the edge mode does not change to directed one (as it should since that relation is directed) but stays in the undirected mode of the second relation. This should be fixed: edge mode should "follow" the relationship.