palantir/blueprint

initially-hidden sub-tabs not styled correctly when first viewed

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#1,544 opened on Sep 10, 2017

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 (4 comments) (5 reactions) (0 assignees)TypeScript (20,263 stars) (2,167 forks)batch import
P2Package: coreType: bughelp wanted

Description

Bug report

  • Package version(s): 1.27.0
  • Browser and OS versions: All browsers, Latest Windows 10 (probably not relevant)

Steps to reproduce

  1. Create a Tabs2 with two or more Tab2. Keep default activeTabId settings (i.e., the first tab is active)
  2. Within the panel component for the second Tab2, create another Tabs2 with two or more Tab2. It doesn't matter if one of these lower-tier tabs is set as the default active tab.
  3. Load page and navigate to the second top-level tab.

Actual behavior

In the panel in the second top-level tab, the active sub-tab is activated (the panel is shown), but the tab itself not styled completely. There is no underline, for example, even though the tab font is shown as active. The same is true for further sub-tabs. See attached image as an example: No sub-tabs in the second top-level panel are rendered correctly (this was initially hidden; there are a total of three sub-tab tier levels in the image). HOWEVER, when a sub-tab other than the active tab is clicked, rendering re-commences as expected.

image

Expected behavior

When navigating to the initially-hidden sub-tabs, the active sub-tab should be styled completely and correctly.

A workaround of course is to only render upon tab selection, but that is not ideal.

Contributor guide

Tech stack
typescriptreactcss
Domain
frontend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
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.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
React knowledgeCSS debugging skillsFamiliarity with blueprint's Tabs2 component
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
55
Research direction
Investigate the Tabs2 component in the blueprint repository, specifically how it handles initially hidden tabs and applies active styling. Look at the component's state management and CSS classes, probably in src/components/tabs2/tabs2.tsx or similar. Reproduce the bug and identify which CSS or logic fails for nested tabs that are not initially visible.