The feature you request does not yet exist, but it is a good idea. I added the limit to save you from yourself. The tree control we use just would not function well for that amount of expansion, and you wold likely end up cursing Skyline as it locked up for a very long time and then continued to perform poorly after that. I wish we had a tree control that functioned as well as the grid control we use in the face of a massive tree, but unfortunately, we do not (yet).
But, I could certainly imagine showing Expand All on the right-click menu for the Targets view, when you have at least 1 parent node selected. I have added the following TODO issue to our issues list to track this request:
Thanks for your feedback.