The QR Codes creator kept its two columns at window widths where there was not room for them, because the sidebar takes 220 pixels that the layout was not counting. The fields could then be sized narrower than their own contents and run across the preview beside them. The creator now switches to a single column below 1200 pixels, and both columns carry a minimum width so neither can be squeezed under its content.
The QR code fields no longer run under the preview
At middle window widths the creator fields could be squeezed narrow and overlap the preview column. They now stack instead.