Prevent crash

app/src/main/java/eu/faircode/email/FragmentDialogFolder.java

@@ -88,7 +88,26 @@ public class FragmentDialogFolder extends FragmentDialogBase {
             @Override
             public void onFocusChange(View v, boolean hasFocus) {
                 if (hasFocus)
-                    etSearch.showDropDown();
+                    try {
+                        etSearch.showDropDown();
+                    } catch (Throwable ex) {
+                        Log.w(ex);
+                        /*
+                            Caused by: android.view.WindowManager$BadTokenException: Unable to add window -- token null is not valid; is your activity running?
+                                    at android.view.ViewRootImpl.setView(ViewRootImpl.java:958)
+                                    at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:381)
+                                    at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:100)
+                                    at android.widget.PopupWindow.invokePopup(PopupWindow.java:1467)
+                                    at android.widget.PopupWindow.showAsDropDown(PopupWindow.java:1316)
+                                    at android.widget.ListPopupWindow.show(ListPopupWindow.java:740)
+                                    at android.widget.AutoCompleteTextView.showDropDown(AutoCompleteTextView.java:1226)
+                                    at eu.faircode.email.FragmentDialogFolder$1.onFocusChange(SourceFile:91)
+                                    at android.view.View.onFocusChanged(View.java:7573)
+                                    at android.widget.TextView.onFocusChanged(TextView.java:10958)
+                                    at android.widget.EditText.onFocusChanged(EditText.java:277)
+                                    at android.widget.AutoCompleteTextView.onFocusChanged(AutoCompleteTextView.java:1125)
+                         */
+                    }
             }
         });