Ensure listers are only on use elements in #svg_group

Previously this included the `use` elements used for the dropdown
arrows, leading to some errors. Using the selector "#svg_group use" only
gets use elements within the svg_group ID.
Also fix some miscellaneous issues that were giving warnings, but not
impeding functionality.

Resolve #318.

src/Controls.js

@@ -405,7 +405,9 @@ function bindElements(insertHandler) {
  */
 function activate(id, insertHandler) {
     $("#" + id).addClass("is-active");
-    insertHandler.insertActive(id);
+    if (document.getElementById(id).classList.contains("insertel")) {
+        insertHandler.insertActive(id);
+    }
 }
 
 /**

src/InsertHandler.js

@@ -136,10 +136,9 @@ function InsertHandler (neonView) {
             editModeButton.innerHTML = "Return to Edit Mode";
             editModeContainer.appendChild(editModeButton);
             document.getElementById("delete").parentNode.parentNode.appendChild(editModeContainer);
+            editModeButton.addEventListener("click", insertDisabled);
         }
 
-        editModeButton.addEventListener("click", insertDisabled);
-
         Notification.queueNotification("Insert Mode");
     }
 

src/Select.js

@@ -22,7 +22,7 @@ export function ClickSelect (dragHandler, zoomHandler, neonView, neon, infoBox)
 
     //Selection mode toggle
     function selectListeners () {
-        var classesToSelect = "use, #svg_group";
+        var classesToSelect = "#svg_group use, #svg_group";
         Controls.initSelectionButtons();
 
         //Activating selected neumes
@@ -217,9 +217,9 @@ export function DragSelect (dragHandler, zoomHandler, neonView, neon, infoBox) {
 
             var nc;
             if ($("#selByStaff").hasClass("is-active")) {
-                nc = d3.selectAll("use, .staff")._groups[0];
+                nc = d3.selectAll("#svg_group use, .staff")._groups[0];
             } else {
-                nc = d3.selectAll("use")._groups[0];
+                nc = d3.selectAll("#svg_group use")._groups[0];
             }
             var els = Array.from(nc);