capturing the left and right arrow keys

in the main planner display with a single day or multiple days displayed the arrow (cursor) keys move the highlight bar up and down the times.

 
I wish to capture the left and right arrow (cursor) keys  to progress the display one day before/after.
 
I do realise this function is achieved with the arrow buttons in the header.
 
 

has been answered by direct email.

next version will have a special new event for this