Difficulty in editing sections of clips

Win 7 64 bit - Audacity 2.1.1

I have problems when trying to copy or delete a secion of a clip. First I pause then select the piece which becomed hightlighted. But the copy/delete is greyed out until you stop. But when you stop the highlighted section disappears. If you stop first the cursor goes right back to the start?

Use “Stop and set cursor” (Shift + A) rather than “Stop”.
http://manual.audacityteam.org/o/man/transport_menu.html#set

Thanks. Very helpful