-        LoadingDialog loading = new LoadingDialog(getResources().getString(R.string.wait_a_moment));
-        FragmentManager fm = getSupportFragmentManager();
-        FragmentTransaction ft = fm.beginTransaction();
-        loading.show(ft, DIALOG_WAIT_TAG);
-
+        Fragment frag = getSupportFragmentManager().findFragmentByTag(DIALOG_WAIT_TAG);
+        if (frag == null) {
+            Log_OC.d(TAG, "show loading dialog");
+            LoadingDialog loading = new LoadingDialog(getResources().getString(R.string.wait_a_moment));
+            FragmentManager fm = getSupportFragmentManager();
+            FragmentTransaction ft = fm.beginTransaction();
+            loading.show(ft, DIALOG_WAIT_TAG);
+            fm.executePendingTransactions();
+        }