tooltips on the base layer are lower in z-index that layers.
This means if the layer doesn't hide other layers and doesn't prevent interaction on the base layer (which is exactly what I need to do), the tips appear underneath layer objects.
Is there anyway to change this behaviour so that tips appear on top of all layers?
Not really, unless you design them so they are never under something that can show on any layer. The whole concept of layers in SL is that they lay over the slide. (Some other apps used to refer to the z-index as layers, but SL uses real layers.)
There are a couple of things you might try. You can lightbox the tooltips, or you can put them in their own layers that don't hide other layers. Those layers can show and hide with a hover.
