I made an SVG interface for displaying/editing diagrams using nw.js (essentially Electron). It would adapt the SVG viewport height and width based on the amount of space that's actively being used so that scrollbars will appear only when needed.
The interface would work perfectly in Chromium and Firefox. But in nw.js I was using their menu api to display a window menu. That menu wasn't part of the DOM-- not sure how nw.js displays that menu but you can't introspect it in devTools. Anyhow, this was somehow creating an off-by-one problem where scrollbars would one pixel too early.
The only way I stumbled upon to fix the issue was to set the SVG style to add "float: left;"
Any ideas on what magic spell this casts? Technically the svg was the only DOM element in the page. I never did figure it out.