[Feature request]: Option to "Expand vertically when space is limited"

[davidhedlund]

Description

The Panel Properties currently include an "Expand" option (enabled by default in Ubuntu MATE). When enabled, it centers the panel content and expands the panel horizontally once all horizontal space is occupied. However, the panel does not expand vertically when horizontal expansion is maxed out.

Proposed Feature

Introduce a new setting in the MATE Panel preferences:

Option name: "Expand vertically when space is limited"

Behavior

• When enabled, the panel automatically increases its height to accommodate additional rows when the Window List exceeds available width.
• When space becomes sufficient again (for example, after closing some windows), the panel height returns to its original size.
• This allows the panel to use only one row under normal conditions while avoiding cramped window buttons in high-load situations.

Motivation

This feature would improve usability and appearance consistency, reducing clutter and maintaining readable window labels. It offers a flexible alternative to the current grouping behavior while avoiding manual resizing. Additionally, it makes better use of the available screen space by utilizing more vertical real estate, allowing the panel to expand and occupy more area on the screen.

Example Scenario

Most distributions set the panel height to 28 px (one row). With the proposed feature, the panel could be configured to 56 px, behaving as a single 28 px row under normal conditions and automatically expanding to the full 56 px when additional space is needed. "Expand vertically when space is limited" enables a more flexible and modern panel behavior, and thus the default panel height can be increased from 28 px to 56 px.

Without the feature request (control)

Configuration

• Panel height: 56px
• Current behavior (or with "Expand vertically when space is limited" disabled):

Panel height behavior

• Static panel height: 56px

With the feature request

Configuration

• Panel height: 56px
• Enabled "Expand vertically when space is limited"

Panel height behavior

• Default (space sufficient): One row of Window List buttons (about 28px height)
• When horizontal space runs out: Panel automatically expands vertically to two rows (height doubles to 56px)
• When windows are closed: Panel height returns to one row (28px)

Additional Notes

If a feature to "Expand vertically when space is limited" is added:

• The existing "Expand" option should be renamed to "Expand horizontally" for clear and logical distinction between the two behaviors.
• The Window List applet in MATE Panel includes an option called "Group windows when space is limited," which helps manage limited space by merging window buttons. This behavior currently activates only when horizontal expansion reaches its maximum, and it should also only apply when vertical expansion has reached its limit.
• The feature should respect the panel’s maximum configured height to avoid unwanted resizing artifacts.

[davidhedlund]

@vkareh Hello! What do you think about this idea? 😀