Unexpected Result of the BeamForceandMoment component

[junjieim]

When parameter EL is input as a tree structure, the expected output is to classify according to the tree structure.

For example, when a tree such as {[PB1 PB2], [PB3 PB4]} is connected to EL, the expected result is also a tree with 2 branches, one for the PB1 PB2 filter result and the other for the PB3 PB4 result.

However, the actual output is like that the {[PB1 PB2], [PB3 PB4]} is flatten as PB1 PB2 PB3 PB4.

Thanks