- $stop_button = $ '<span class="button">stop drawing</span>'
- $stop_close_button = $ '<span class="button">stop drawing, close loop</span>'
+ $stop_button = $ '<span class="button" title="keyboard shortcut: space">stop line</span>'
+ $stop_close_button = $ '<span class="button" title="keyboard shortcut: O">stop line, close loop</span>'
+ $cancel_button = $ '<span class="button" title="keyboard shortcut: Esc">cancel line</span>'