Is your feature request related to a problem? Please describe.
Sometimes an operation has to be applied on multiple lines of disassembled instructions.
Allowing for multiline selection and operating on those multiple lines can drastically eliminate redundant workload during binary analysis.

Describe the solution you'd like
Allow selection of multiple lines by drawing a rectange with the mouse (click-hold-move-release left mouse button).
Allow adding aditional individual lines by shortcut like Shift+Left Click.

Describe alternatives you've considered
Context menu entry for multiple line selection (not recommended due to unnecessarily nested UI actions).