All day header out of sync with main schedule body after browser zoom

[matsbryntse]

[ExtAnimal]

calendar.modes.week.scrollable.hasScrollbar() is somehow returning false, so the header row is no longer accounting for the visible vertical scrollbar in the detail view, so each column is out of step by scrollbarWidth / 7 pixels.

Have to check how hasScrollbar functions when zoomed.

[ExtAnimal]

Needs:

    hasScrollbar(axis = 'y') {
        const { element } = this;

        if (element && DomHelper.scrollBarWidth) {
            const
                vertical   = axis === 'y',
                dimension  = vertical ? 'Width' : 'Height',
                clientSize = element[`client${dimension}`],
                borderSize = parseInt(DomHelper.getStyleValue(element, `border${vertical ? 'Left' : 'Top'}Width`)) + parseInt(DomHelper.getStyleValue(element, `border${vertical ? 'Right' : 'Bottom'}Width`)),
                difference = ((element[`offset${dimension}`] - borderSize) - clientSize) * window.devicePixelRatio; //<-

            // If the difference between the content width and the client width is
            // scrollBarWidth, then we have a scrollbar
            return Math.abs(difference - DomHelper.scrollBarWidth) < 2;
        }
    }

[ExtAnimal]

Hm no. That accounts for zooming happening after the scrollbar width has been read as 15. Zoom change should uncache scrollbarWidth so that it gets recalculated.

Unfortunately, there's no reliable way to detect zoom. So then getScrollbarWidth will have to cache the devicePixelRatio at the time of measuring, and then when called again, see if it's changed, and if so, uncache the scrollbarWidth so that it measures it at the new zoom setting.

[ExtAnimal]

https://github.com/bryntum/bryntum-suite/pull/1905