[BUG] Three Column - Middle column textarea can not be expanded

[aleung]

Which userscript
Three Column Adjustable

Describe the bug
When switch to three column layout, the middle column textarea is short and can only show 3 lines. It isn't able to drag to enlarge. Screenshot is attached below.

To Reproduce
Steps to reproduce the behavior:

1. On any stackoverflow question page, for example 'https://stackoverflow.com/questions/67745944/openapi-path-query-parameters-nested-structure-serialization'
2. Click on 'Open 3-column layout'
3. See error

Expected behavior
The textarea should fill the space or is able to resize by dragging.

Environment (please complete the following information):

• OS: Ubuntu 18.04.6 LTS
• Browser: Vivaldi 5.2.2623.41 stable (64-bit) (Chrome)
• Userscript Manager: Violentmonkey

Additional context
Add any other context about the problem here.

[aleung]

The bug exists only on adjustable version. The non-adjustable version works fine.