How to reproduce

• I have two open tools in right area, all others areas are empty
• Collapse the right area
• Move a tool from collapse area to central area (or other area)

There is JS error and the tool is not moved

ZonedTabsToolsLayout.js:476
Uncaught TypeError: Cannot read property 'ownerCt' of null

Then when I click on collapsed tool, blank area appear (see screenshot) and I can not do anything, I need to reload the application.