This was an issue introduced with dojo 1.7. We will fix it in the next release.
At this moment, the fix you can apply is to set a bunch of events as null when deactivating the toolbar. For instance, the sample:
http://help.arcgis.com/en/webapi/javascript/arcgis/demos/toolbar/toolbar_draw.html
can be modified as:
function addToMap(geometry) {
toolbar.deactivate();
toolbar._onMouseDownHandler_connect = toolbar._onMouseMoveHandler_connect =
toolbar._onMouseDragHandler_connect = toolbar._onMouseUpHandler_connect =
toolbar._onClickHandler_connect = toolbar._onDblClickHandler_connect =
toolbar._onKeyDown_connect = toolbar._redrawConnect = null;
...
}