src/vs/workbench/electron-sandbox/window.ts/NativeWindow/getWindowMinimumWidth
class NativeWindow:	private getWindowMinimumWidth(panelPosition: Position = this.layoutService.getPanelPosition()): number {

		// if panel is on the side, then return the larger minwidth
		const panelOnSide = panelPosition === Position.LEFT || panelPosition === Position.RIGHT;
		if (panelOnSide) {
			return WindowMinimumSize.WIDTH_WITH_VERTICAL_PANEL;
		}

		return WindowMinimumSize.WIDTH;
	}