Top toolbar mounting method can slow down editor

[bfintal]

// src/editor/plugins/top-toolbar-button/index.js
subscribe( () => {
	setTimeout( () => {
		const toolbar = document.querySelector( '.edit-post-header-toolbar' )
		...
	}, 100 )
} )

Fires on every wp.data store change (every keystroke/selection); each fire schedules a setTimeout doing 2–3 querySelectors. Unthrottled; timeouts stack.

Note: This issue only exists in Gutenberg

Recommendation: debounce + MutationObserver on the toolbar instead of a global store subscription.