Input Move Boxes reorder buttons throws JS error

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: Master
• Fix Version/s: 7.1.10 DXP FP5, 7.1.10.1 SP1, 7.1.2 CE GA3, 7.1.X, Master
• Component/s: JS APIs and Utilities
• Labels:
  • liferay-dxp-71-sp1
  • liferay-fixpack-dxp-5-7110
• Branch Version/s:
  7.1.x
• Backported to Branch:
  Committed
• Fix Priority: 5
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/65506

When trying to reorder options in the Input Move Boxes multiple select, a JS error is thrown.

Steps to reproduce

1. Control Panel -> Configuration -> Instance Settings -> Miscellaneous
2. Go to the Available Languages section and try to reorder the Current Languages.

Excepted Results

• Options reorder without any JS errors

Actual Results

• Options do not reorder
• Down arrow throws JS error: Uncaught TypeError: selectedItems.reverse is not a function
• Up arrow throws JS error: Uncaught TypeError: selectedItems.forEach is not a function