src/vs/workbench/contrib/notebook/browser/viewParts/notebookEditorToolbar.ts/NotebookEditorToolbar/_cacheItemSizes
class NotebookEditorToolbar:	private _cacheItemSizes(toolbar: ToolBar) {
		const actions: IActionModel[] = [];

		for (let i = 0; i < toolbar.getItemsLength(); i++) {
			const action = toolbar.getItemAction(i);
			if (action) {
				actions.push({
					action: action,
					size: toolbar.getItemWidth(i),
					visible: true,
					renderLabel: true
				});
			}
		}

		this._primaryActions = actions;
	}