The snap box is the area around your cursor that allows Vectorworks to snap onto…
Vectorworks Tip # 134 – Interactive settings – Pre-Selection Colour
The standard Vectorworks pre-selection colour is orange. The standard Vectorworks colour for selected objects is also orange, which makes it hard to see when object is selected and when it is pre-selected. This can cause some confusion. If you change the pre-selection colour it to make it easier to see the difference between selected and pre-selected objects.