Shrink back down a JPanel inserted as InlayComponent

IntelliJ Platform
1

We insert a JPanel above some selected code.
What might be the reason it currently:

  1. Properly expands to fill the entire screen when I increase the available space (e.g. reduce size of Project Tree View)
  2. Does not shrink to fill the entire screen when I reduce the available space (e.g. increase size of Project Tree View)
2

Turns out wmin 0 as a MigLayout definition solves the issue.
More info here: