SP810 - QA build

Fixed another (different) Mark & Move Branches that is throwing an "Object reference set to an instance" message. In this case, right-clicking on a cell that is contained in a lowest branch that does not go down to the cell’s branch or the parent branch is not allowed. The example Sugesh showed me was a Design Requirement Usage branch that was marked and being moved by right-clicking on another Design Requirement Usage cell, but the cell was contained in a lowest branch that only went down to Design Function Group, which is two branch levels above Design Requirement Usage. The code has been changed to display the “Move not allowed” message in this case. Note that if you select a Design Function in the Design Function Usage branch, this will create a Design Function Usage branch and then the move can be done (since the parent branch exists). Or, if a Design Requirement is selected in the empty Design Requirement Usage branch causing a Design Requirement Usage branch to be created, then the move can also be done (since the branch exists). Will be available for build on 10/08/2018