Bug 240644 – Web Inspector: Computed Panel: Assertion Failed: Cannot remove view which isn't a subview. ComputedStyleSection

• Component: Web Inspector
• Status: RESOLVED FIXED

[Razvan Caliman]

```
[Error] Assertion Failed: Cannot remove view which isn't a subview.
ComputedStyleSection {_listeners: Multimap, _element: <div class="computed-style-section">, _parentView: null, _subviews: [], _dirty: false, …}
	removeSubview (View.js:127)
	layout (ComputedStyleDetailsPanel.js:216)
	_layoutSubtree (View.js:308)
	_layoutSubtree (View.js:319)
	_layoutSubtree (View.js:319)
	_visitViewTreeForLayout (View.js:378)
```

The root cause of this failed assertion is an accumulation of orphaned `WI.ComputedStyleSection` instances in `this._detailsSectionByStyleSectionMap` from `WI.ComputedStyleDetailsPanel`. 

When `WI.ComputedStyleDetailsPanel.layout()` is called to reflect the latest selected node's variables, the previous `WI.ComputedStyleSection` view instance for ungrouped variables is accidentally kept around even though its host DOM node was removed. When attempting to remove this view on the next `layout()` run, this orphaned instance has no host node that belongs to the parent view so the assertion is hit. The issue gets progressively worse on each `layout()` run by accumulating more orphans.

[Radar WebKit Bug Importer]

<rdar://problem/93571902>

[Razvan Caliman]

Pull request: https://github.com/WebKit/WebKit/pull/782

[EWS]

Committed r294506 (250763@main): <https://commits.webkit.org/250763@main>

Reviewed commits have been landed. Closing PR #782 and removing active labels.