Selection in fusion tends to be difficulty for me. One of the main reasons is that even after going though trouble to select something like though a long click and picking the item from a list, the very next thing I need to do to it like drag it(e.g, moving a joint) I can't do. Clicking always seems to clear the current selection and then hit tests to the wrong item again. Please either provide some other modifier the only acts on the selected items, or change the hit testing behavior to prefer the object under the cursor that is already selected.