Left sidebar is fixed-width and cannot be collapsed or resized

Summary

The left sidebar in Rocket.Chat is currently fixed-width and always fully expanded. On laptops, smaller screens, or split-screen workflows, this significantly reduces the usable area for conversations and content.

This issue requests support for collapsing the sidebar into a compact icons-only mode, with optional resizing as a future enhancement, while keeping the existing behavior unchanged by default.

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Problem Description

• The sidebar always occupies a fixed horizontal space
• Users cannot reduce its footprint without browser zoom or custom CSS
• This impacts focus and usability, especially on smaller screens

Many modern collaboration tools provide a compact or collapsible sidebar to address this problem.

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Requested Behavior (Initial Scope)

Collapsible Sidebar (Icons-Only Mode)

• Ability to collapse the left sidebar via a toggle action
• Default behavior remains unchanged (expanded)
• In collapsed mode:
  • Only icons are displayed for rooms, channels, and DMs
  • Text labels are hidden
  • Sidebar width is reduced to a minimal fixed size

Tooltip Support (Initial Stage)

• On hover (or focus) in collapsed mode, show a tooltip with:
  • Full room or user name
  • Last message preview (shortened)

Example tooltip content:

#general
"Last message preview…"

This allows users to retain context without expanding the sidebar.

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UX & Accessibility Considerations

• Keyboard-accessible toggle
• Tooltips accessible via keyboard focus
• Clear hover and focus states
• No impact on mobile layouts
• Fully backward compatible

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Suggested Follow-Ups (Optional / Later)

These are optional ideas and not required for the initial implementation:

1. State Persistence

   • Remember collapsed / expanded state using user preferences or local storage

2. Resizable Sidebar

   • Drag handle to resize sidebar width
   • Automatically switch to icons-only mode below a width threshold
   • Persist preferred width per user

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Potentially Related Areas

• packages/ui-client/sidebar
• packages/ui-contexts
• Fuselage UI components (tooltips, layout primitives)

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Current Status

There does not appear to be an existing implementation for:

• Collapsing the sidebar into an icons-only mode
• Tooltip-enhanced compact sidebar
• Resizable sidebar width

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Contribution Intent

I’m interested in contributing to this issue incrementally, starting with the initial collapsible icons-only sidebar, based on maintainer feedback and guidance.

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Benefits

• Better screen space utilization
• Improved focus on conversations
• Familiar UX pattern for users
• Optional and non-breaking enhancement

Start with packages/ui-client/sidebar and packages/ui-contexts, then review the referenced Fuselage tooltip and layout components. Define the initial scope as an expanded-by-default, icons-only collapse mode with keyboard-accessible toggle and focusable tooltips, while preserving mobile behavior. Treat persistence and resizing as later follow-ups.