Use Block Select (aka Column mode) to manipulate your VHDL code (Manual).
See also
- Why can't HDL designers live without block selection mode? (opinion)
- VHDL IEEE 1076-2008 Grammar (blog post)
- Testbench generation with Wavedrom (opinion)
- PoC - A Pile of Cores (opinion)
- Context Sensitive Autocompletion (screencast)