Canvas background and keyboard shortcuts

The canvas is not simply an inert place for the canvas items to exist. There is also a background context menu, giving access to the edit menu functionality such as cut/copy/paste, and also keyboard entry.

Special keys:

F1	context sensitive help
Shift	enter panning mode
$\leftarrow,\rightarrow,\uparrow,\downarrow$	adjust sliders, adjust Ravel slicers

The following keystrokes insert an operation

+	add
-	subtract
*	multiply
/	divide
^	pow
%	percent operator
&	integral
=	Godley table
@	plot
#	start a text comment, finish with return

Typing any other character, then return will insert an operation (if the name matches), or otherwise a variable with that name.