src/vs/workbench/contrib/notebook/browser/viewParts/notebookEditorToolbar.ts/FixedLabelStrategy/_calculateFixedActions
class FixedLabelStrategy:	protected _calculateFixedActions(leftToolbarContainerMaxWidth: number) {
		const primaryActions = this.editorToolbar.primaryActions;
		const lastItemInLeft = primaryActions[primaryActions.length - 1];
		const hasToggleMoreAction = lastItemInLeft.action.id === ToggleMenuAction.ID;

		let size = 0;
		const actions: IActionModel[] = [];

		for (let i = 0; i < primaryActions.length - (hasToggleMoreAction ? 1 : 0); i++) {
			const actionModel = primaryActions[i];

			const itemSize = actionModel.size;
			if (size + itemSize <= leftToolbarContainerMaxWidth) {
				size += ACTION_PADDING + itemSize;
				actions.push(actionModel);
			} else {
				break;
			}
		}

		actions.forEach(action => action.visible = true);
		primaryActions.slice(actions.length).forEach(action => action.visible = false);

		return {
			primaryActions: actions.filter(action => (action.visible && action.action.id !== ToggleMenuAction.ID)).map(action => action.action),
			secondaryActions: [...primaryActions.slice(actions.length).filter(action => !action.visible && action.action.id !== ToggleMenuAction.ID).map(action => action.action), ...this.editorToolbar.secondaryActions]
		};
	}