Browser scroll bar disappear after report a thread

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 7.2.X, Master
• Fix Version/s: 7.3.1 CE GA2, 7.3.2 CE GA3, 7.3.10 DXP GA1, Master
• Component/s: Message Boards
• Labels: None
• Story Points: 1
• Fix Priority: 2
• Sprint: LIMA | #14 | Feb18-Mar03
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/85038
• QA Test Name:
  • Manual_Environment_Collaboration
• QA Test Score: 5

Steps to reproduce:

1. Start portal and login.
2. Add MB to home page, post a thread with any title and content.
3. Report the thread by pressing the "flag" button.
4. Select any reason in the dropdown list, close the dialog.
5. Try to scroll up and down.

Expceted result:
Page could scroll up and down, the scroll bar appears.
Actual result:
Scroll bar disappears, page can not scroll up and down.

Notes: It would be resolved by refreshing the page.