mozilla-mobile/firefox-ios

[Swipe tabs] Darker square becomes visible when swiping right on the first tab in the tab list

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#29,181 opened on Sep 5, 2025

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Contributor OKGood first issue

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Description

Steps to reproduce:

  1. Open Firefox.
  2. Make sure you have more tabs opened
  3. On the first tab in the list, perform a right-swipe gesture.
  4. Observe the UI during the swipe.

Expected result: Only the background color should be visible during the swipe interaction

Actual result: A darker square is visible during the right-swipe gesture.

Device & Build Information:

  • Device: iPhone 14+ (iOS 16.0.3)
  • Build version: v143.0 (60740)

:information_source: Reference Person

@FilippoZazzeroni

┆Issue is synchronized with this Jira Bug

Contributor guide

Research direction
Investigate the tab bar swipe animation implementation. Look for code that handles the visual feedback during the swipe gesture, especially when swiping right on the first tab. The darker square might be a leftover overlay from a previous state. Trace the logic to ensure that overlays are properly removed when the tab is the first one.
Tech stack
swiftios
Domain
mobile
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
SwiftiOSUIKitGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70