Blogs - Preview button disappears if title was missing

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 6.1.0 CE GA1, 6.2.0 CE M2
• Fix Version/s: --Sprint 12/11, 6.1.0 CE RC1, 6.1.20 EE GA2, --Sprint 11/12, 6.2.0 CE M2
• Component/s: Collaboration, Collaboration > Blogs
• Labels:
  • QA-R
• Branch Version/s:
  6.1.x
• Backported to Branch:
  Committed
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/4338

On creating blog entry, if user forgot to enter blog title and presses "Preview", an error message is being displayed, but the button is missing.
Expected behaviour - error message and "Preview" button.