Hi Jeff,
As best I can tell, the results are the same in ABD CONNECT EAP 1 - a branch cannot be moved along the length of the main duct (connected by a takeoff) when there is a fitting and duct on the other end; i.e., it will not auto-stretch that other duct. However, in your example the vertical duct can be moved instead which will move the horizontal piece, since in that scenario the horizontal piece itself is not being stretched. If that makes sense.
As best I can tell, the results are the same in ABD CONNECT EAP 1 - a branch cannot be moved along the length of the main duct (connected by a takeoff) when there is a fitting and duct on the other end; i.e., it will not auto-stretch that other duct. However, in your example the vertical duct can be moved instead which will move the horizontal piece, since in that scenario the horizontal piece itself is not being stretched. If that makes sense.