Qt Quick emulation layer crashed when opening a ui.qml file

I'm following along with the example here:

https://codereview.qt-project.org/#/c/251488/

I had just finished modifying PushButton.ui.qml as instructed. I hadn't saved anything yet. The instructions say:

Double-click Screen01.ui.qml in the Project sidebar view to open it on the canvas.

I accidentally opened loginui1.qml instead (via Navigator > Project), so then I found Screen01.ui.qml in the tree view and opened it, but saw an error:

When I clicked on "Go to error", it brought me here:

import QtQuick 2.10
import loginui1 1.0

Rectangle {
    width: Constants.width
    height: Constants.height
    
    
    Text {
        text: qsTr("Qt Account")
        font.pointSize: 24
        anchors.centerIn: parent
        font: Constants.font
    }
    
    Image {
        id: image
        x: 8
        y: 28
        width: 106
        height: 81
        source: "qt_logo_green_rgb.svg"
    }
}

If I hit Ctrl+Shift+S to save all files and then try to open the file in the form editor again, it can open the file without crashing, but I need to restart Design Studio to be able to e.g. drag items onto the canvas.