Popup for Scheduler event can't be dragged with a single mouse click

[SergeyMaltsev]

Reported here
https://www.bryntum.com/forum/viewtopic.php?f=44&t=12653

Can be reproduced in https://www.bryntum.com/examples/scheduler/ with this config.
Popup can be dragged/moved with second mouse click on it only.

   listeners : {
        eventClick : (event) => {
            const popup = new Popup({
                header    : 'Popup-Header',
                draggable : true,
                cls       : 'scheduler-popup-w',
                html      : `Popup-Body`
            });
            popup.activeTarget = event.event.srcElement;
            popup.showBy(event.event.srcElement);
        }
    }

[SergeyMaltsev]

Adding focusable : true, to Popup config is workaround for this issue.

[matsbryntse]

Seems to work fine in latest