src/vs/base/browser/ui/sash/sash.ts/Sash/state
class Sash:	set state(state: SashState) {
		if (this._state === state) {
			return;
		}

		this.el.classList.toggle('disabled', state === SashState.Disabled);
		this.el.classList.toggle('minimum', state === SashState.Minimum);
		this.el.classList.toggle('maximum', state === SashState.Maximum);

		this._state = state;
		this._onDidEnablementChange.fire(state);
	}