Created attachment 131794 [details]
Screen recording showing the problem

SUMMARY
When GlobalDrawer is used, and the window is resized to a narrow width and the drawer is hidden, subsequent resizing to a wide width will cause it to disappear entirely.

A screen recording which explains this better is attached.


STEPS TO REPRODUCE
1. Use GlobalDrawer, with the modal and handleVisible properties both set to !root.widescreen (code attached)
2. Resize the window to a narrow width, such that the drawer hide button appears
3. Hide the drawer so it collapses into the button
4. Resize the window back to a wide width

OBSERVED RESULT
The drawer disappears entirely. The only way of getting it back is to resize to a narrow width again.

EXPECTED RESULT
The drawer restores to its full size.

SOFTWARE/OS VERSIONS
KDE Plasma Version: 5.19.5
KDE Frameworks Version: 5.74.0 (package kirigami2-5.74.0-1-x86_64)
Qt Version: 5.15.1

MINIMAL CODE EXAMPLE

import QtQuick.Layouts 1.1
import org.kde.kirigami 2.0 as Kirigami

Kirigami.ApplicationWindow {
    id: root
    visible: true
    width: 800
    height: 500

    globalDrawer: Kirigami.GlobalDrawer {
        id: drawer

        modal: !root.wideScreen
        handleVisible: !root.wideScreen

        header: Kirigami.Heading {
            level: 1
            text: "Header"
            Layout.fillWidth: true
        }
    }
}