Collapsing lists in Planners
From Planfix
You can collapse lists in a planner to make it easier to work with them. To do this, simply click the double-arrow icon to the right of the list title, or click anywhere on the title bar:
You can work with a collapsed list in the same way you work with a regular list. For example, you can change its position or drag and drop tasks to it:
You can collapse and expand individual lists positioned on top of each other. This lets you fit more information on your screen at once: