Fixes from review.

src/app.js

@@ -209,11 +209,11 @@ var run = function () {
     })
   })
   files.event.register('fileRemoved', function (path) {
-    editor.discard(path)
     if (path === ui.get('currentFile')) {
       ui.set('currentFile', '')
       switchToNextFile()
     }
+    editor.discard(path)
     refreshTabs()
   })
   files.event.register('fileAdded', function (path) {

src/app/file-explorer.js

@@ -77,8 +77,8 @@ function fileExplorer (appAPI, files) {
   `
 
   appUI.register('fileChanged', (changedFiles) => {
-    if (changedFiles[0] == 'currentFile') {
-      fileFocus(files.get('currentfile'))
+    if (changedFiles[0] === 'currentFile') {
+      fileFocus(files.get('currentFile'))
     }
   })
   fileEvents.register('fileRemoved', fileRemoved)