ToolbarS

Toolbars can be turned off using the network view menu.  

Mode Toolbar

This toolbar allows you to set the edit mode for the network, visible as the cursor graphic.

Selection mode. Select nodes and weights by lassoing or left-clicking. Hotkey: S.
Text mode Text mode.  In this mode text can be added anywhere in the network panel.  Text objects can be subsequently edited by double-clicking on them. Text can be formatted by right clicking on a text object and selectingText Properties.... Hotkey: T.
Wand Wand mode. Can be used to inject activation to nodes quickly for testing. Hotkey: I. See wand tool.
ZoomFit Auto-zoom. Single clicking zooms to fit objects on screen. Double clicking toggles auto-zoom mode. When in auto-zoom mode moving and creating objects will automatically fit all objects to page.

Run Toolbar

This toolbar is for running the network, independently of the workspace. It is hidden by default (because it can be easily confused with workspace run / step) and must be turned on using the view menu.

Play Run network . Repeatedly iterates the network. Note that the image on the button becomes that of a "stop" button Stop. Pressing this button will stop the network. Thus the play/stop button acts as a toggle switch.
Step Step through one update cycle (Also keyboard space and S, depending on interaction mode).

Edit Toolbar 

This toolbar allows you to create and delete neurons, and change their state.

Rand Set all selected nodes (weights and or nodes) to a random value (Also keyboard R). Randomization is a uniform distribution between the upper and lower bounds set for each neuron or weights.
Eraser Set all selected neurons to 0. Weights are ignored. (Also keyboard C)
Add neuron Create a neuron at last position clicked on screen. (Also keyboard N)
Delete Neuron Delete currently selected neurons. (Also keyboard delete or backspace).