@vinaygopal you could customise your Spinbox and set your own TextInput, that one still has the selectByMouse, even if 5.15.8
https://doc.qt.io/qt-5/qtquickcontrols2-customize.html#customizing-spinbox
https://doc.qt.io/qt-5/qml-qtquick-textinput.html#selectByMouse-prop