When there are several nodes on canvas, we can select different nodes using the arrow keys.
However, this feature is virtually unusable, because we cannot predict which node would be selected if we use an arrow key.
The selection jumps to a different node depending on the relative location of the nodes. So an upArrow is supposed to select a node that is above the currently selected node.
But start with a stack of nodes that are vertically stacked. Then start moving one node sideways and keep repeating the experiment. At one point of time, the node will be completely ignored. Likewise there seem to be multiple factors that affect how the selection changes.
Any keyboard action is useful only if it is consistent and repeatable.
Therefore the arrows keys are not usable to switch the selection to a different node.
In fact, there is an another problem: If we already have multiple nodes selected, and if we accidentally touch a arrow key, the selection is destroyed, and a single node is selected. It is impossible to restore the earlier selection.
We don't want this behavior either.
Thus, on the whole, it is better to let the user nudge the selection with the arrow keys; instead of changing the node-selection.
(Nudging means moving the selection by one pixel. But different combinations of modifier keys like SHFT/CTRL/ALT can be used to accelerate the movement by different factors; as in case of graphic/video editors.)
