I am using DraftSight on two different computers. On one, I can select multiple entities by clicking on them successively, and they are added to the selection. To de-select I hold the shift key down and click.

On the other computer I have to hold the shift key down to undertake successive selections, and if I want to remove from the selection I similarly hold the shift key down and click on the entity again. 

I would like to make both machines operate the same way, by adding entities with a click. I have looked in 'Tools", 'Options', 'User Preferences', 'Drafting Options', 'Entity Selection', which I thought would be a good place to start, but can't see anything obvious. I presume I have to turn a setting option on or off somewhere, but where??