--- a/browser/components/preferences/in-content/search.js
+++ b/browser/components/preferences/in-content/search.js
@@ -101,21 +101,26 @@ var gSearchPane = {
       if (e.name == currentEngine)
         list.selectedItem = item;
     });
   },
 
   handleEvent: function(aEvent) {
     switch (aEvent.type) {
       case "click":
-        if (aEvent.target.id != "engineChildren" && aEvent.target.id != "removeEngineButton") {
+        if (aEvent.target.id != "engineChildren" &&
+            !aEvent.target.classList.contains("searchEngineAction")) {
           let engineList = document.getElementById("engineList");
           // We don't want to toggle off selection while editing keyword
-          // so proceed only when the input field is hidden
-          if (engineList.inputField.hidden) {
+          // so proceed only when the input field is hidden.
+          // We need to check that engineList.view is defined here
+          // because the "click" event listener is on <window> and the
+          // view might have been destroyed if the pane has been navigated
+          // away from.
+          if (engineList.inputField.hidden && engineList.view) {
             let selection = engineList.view.selection;
             if (selection.count > 0) {
               selection.toggleSelect(selection.currentIndex);
             }
             engineList.blur();
           }
         }
         if (aEvent.target.id == "addEngines" && aEvent.button == 0) {

--- a/browser/components/preferences/in-content/search.xul
+++ b/browser/components/preferences/in-content/search.xul
@@ -75,16 +75,17 @@
 
       <hbox>
         <button id="restoreDefaultSearchEngines"
                 label="&restoreDefaultSearchEngines.label;"
                 accesskey="&restoreDefaultSearchEngines.accesskey;"
                 />
         <spacer flex="1"/>
         <button id="removeEngineButton"
+                class="searchEngineAction"
                 label="&removeEngine.label;"
                 accesskey="&removeEngine.accesskey;"
                 disabled="true"
                 />
       </hbox>
 
       <separator class="thin"/>