CopyableLabel: Fix select all on Safari

By using a deferred command here for the select all and focus we
can better handle Safari's event model, which requires the UI to
update before select all will work.

Change-Id: Ie3a190f3567d3cb05beb3714d6e2b4b02ad520ac
Signed-off-by: Shawn O. Pearce <sop@google.com>
diff --git a/src/main/java/com/google/gwtexpui/clippy/client/CopyableLabel.java b/src/main/java/com/google/gwtexpui/clippy/client/CopyableLabel.java
index e2e91ed..1beee4c 100644
--- a/src/main/java/com/google/gwtexpui/clippy/client/CopyableLabel.java
+++ b/src/main/java/com/google/gwtexpui/clippy/client/CopyableLabel.java
@@ -209,8 +209,13 @@
 
     textLabel.setVisible(false);
     textBox.setVisible(true);
-    textBox.selectAll();
-    textBox.setFocus(true);
+    DeferredCommand.addCommand(new Command() {
+      @Override
+      public void execute() {
+        textBox.selectAll();
+        textBox.setFocus(true);
+      }
+    });
   }
 
   private void hideTextBox() {