Issue description

When configuring swimlanes in a board, the JQL and the Description fields are narrow: they don't use the entire space available and they can't be adjusted/expanded to use the full width available.

Environment

Reproduced on Chrome, Firefox and Safari while using Jira 8.4.2.

Steps to reproduce

1. Install Jira Software 8.4.2
2. Create a new Jira Software project using the Scrum template
3. Open any board and go to Board > Configure > Swimlanes
4. Change the setting Base Swimlanes on to Queries

Observed behavior

The JQL and Description fields can't be expanded to use the full width available:

Expected behavior

The JQL and Description fields are using the full width available and can also be adjusted, like it was the case on previous Jira versions (for example 8.1.0):

Workaround

None