Combo box off center with centered parent container

[hiikion]

OS: Nobara linux 37

The code:

import nigui
app.init()

var window = newWindow("window")
window.width = 350.scaleToDpi
window.height = 200.scaleToDpi


var baseContainer = newLayoutContainer(Layout_Vertical)
baseContainer.widthMode = WidthMode_Expand
baseContainer.xAlign = XAlign_Center
baseContainer.yAlign = YAlign_Center
window.add(baseContainer)

var Combo = newComboBox(@["1", "2", "3"])
baseContainer.add(Combo)

window.show()
app.run()

in theory, it should center the combo, but it leans to the right:

other widgets like buttons and text boxes do center