Wrong thumbnail show in page design options sidebar panel for the inherited stylebook

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: Master
• Fix Version/s: 7.3.X, Master
• Component/s: Pages > Page Editor
• Labels: None
• Branch Version/s:
  7.3.x
• Backported to Branch:
  Committed
• Fix Priority: 3
• Git Pull Request: https://github.com/liferay-echo/liferay-portal/pull/2653

Steps to reproduce 

• Add a Stylebook SB1
• Set a thumbnail to the stylebook
• Create a Content page
• Set the stylebook to the newly created stylebook in the sidebar panel
• Reload page

Expected result

There are two entries in the stylebook sidebar panel, one that said "inherited from master" which doesn't have a thumbnail, and another entry SB1 with the selected thumbnail

Actual result

Both entries have the same thumbnail

Note: While you are trying to reproduce this, you may encounter some problems related to https://issues.liferay.com/browse/LPS-120692, so it is better to try with different browsers if something fails