Xforms repeat setIndex inconsistent between 1.4 and 1.6

The difference is due to a difference in deferred update behaviour between the two versions. In 1.4, what is happening is that first time the action is executed, the setindex is attempting to set the index of the repeat to 2, whilst the repeat still has only one item in it (although the nodeset to which it is bound has 2 nodes). The behaviour of setindex, when given an index greater than the size of the repeat, is to set the index to the last item in the repeat (which, in this case, is also the first).

In 1.4, the action element is a boundary for deferred update. In order to see the same effect in both versions, move the setindex out of the action element, not forgetting to give it its own ev:event attribute.

<xf:setindex repeat="rtx1Sub" index="index('rtx1Sub')+1" ev:event="DOMActivate"/>

This ensures that the repeat is updated before the index is set.

Since XForms 1.1, there are certain actions, such as setindex, that force any previously deferred updates to occur, prior to execution. (see section 10, XForms Actions, for details.