Description

When the columns addon is enabled, the Blockly workspace dimensions are incorrect.

Steps to reproduce

1. Enable two-column category menu
2. Scroll as far left as possible

Note that the horizontal scrollbar doesn't reach the left edge of the code area:

Demonstration(s) and additional context

No response

Environment

Browser: Edge 153 dev
Scratch Addons version: 86b4c0d
Operating system: Windows