When moving around within the model tree, only the mouse can be used to select a model tree entry. The up/down arrow cursor keys move a dotted box around the model tree, but the selected item remains what the user last clicked on. (WF4)
I frequently find myself in an assembly, clicking one sub-assembly after another until the one I am interested in is highlighted in the model.
At present, it goes:
look at the model tree;
click the mouse on the next sub-assembly;
look at the model to see whether the item of interest has highlighted;
back to the model tree;
click the next one;
back to the model to see if I have hit the target;
Allow the user to move the selection within the model tree using either the mouse click or the up/down arrows.
In this scenario, I simply look at the model and press the down arrow repeatedly until the item of interest turns red.