helpandsupport.xara.com page broken

[korfob]

The Help/More Xara Designer Pro+/Support pages menu option leads me to a broken page, in both Chrome and Firefox:
https://helpandsupport.xara.com/xara_desktop/introduction/index.html?f=Productesigner_Pro+

About 1 second after the browser loads the page, the vertical scrollbar disappears, after which the page cannot be scrolled up or down using the mouse scrollwheel, the up/down arrow keys, or the PgUp/PgDn keys (nor the absent scrollbar). The top nav is empty except for the 'X' logo, which is unclickable. The whole page can be viewed only by zooming way out (see screenshot); however the links are unclickable. So one cannot advance past the page or navigate away from it (other than the browser Back button, or closing the page).

In both Chrome and Firefox, the browser console shows this error:

Uncaught TypeError: rob_toolbarList is null
    popPanel https://helpandsupport.xara.com/template/xaraskin/robofix_xara.js:18
    setTimeout handler*popPanel https://helpandsupport.xara.com/template/xaraskin/robofix_xara.js:9
    EventListener.handleEvent* https://helpandsupport.xara.com/template/xaraskin/robofix_xara.js:5
robofix_xara.js:18:12
    popPanel https://helpandsupport.xara.com/template/xaraskin/robofix_xara.js:18
    (Async: setTimeout handler)
    popPanel https://helpandsupport.xara.com/template/xaraskin/robofix_xara.js:9
    (Async: EventListener.handleEvent)
    <anonymous> https://helpandsupport.xara.com/template/xaraskin/robofix_xara.js:5

Firefox 115.5.0esr (64-bit)
Chrome 120.0.6099.110 (Official Build) (64-bit)
Win11