Navigate

Up-Down-Right-Left

Tab, Shift-Tab

PageUp, PageDown

Home, End

Mouse movement

Edit any given cell

Enter key, just start typing

Double click

Insert new line - new issue

(coming soon)

Insert

"+" icon at the beginning of the line, Context menu

Delete line

Delete

Context menu

Deletes the whole issue and its subtasks from that point

Copy-Paste

Ctrl+C, Ctrl+V

Context menu

Edit issue in JIRA dialog

Ctrl+E

Context menu

you can even edit Quick Sub-tasks with it