I kept five browser tabs open all day while watching markets — a chart, an economic calendar, a heatmap, a quote — and spent the whole session alt-tabbing. Window tiling let me see all five at once, but each pane was still the whole page: mostly nav and ads, with the number I actually wanted rendered tiny. The first attempt was a local HTML file with iframes. That died fast. Most of the sites I wanted send X-Frame-Options or CSP headers that refuse to load in a frame, and the few that loaded had no login state. So it became a native app with a real WKWebView per pane. Cropping a region was the easy part. Making the crop stay on that region was the whole project. Resize a pane and the region would drift somewhere else on the page — WKWebView's automatic content inset was shifting things underneath me. The fix was to disable that inset and place the region with a layer transform, using the crop view's own size as the scaling base. Most of the development time went into that one bug. Still unsolved: a cropped pane is view-only, clicks pass through it. You toggle the crop off to interact. I'd genuinely like to know whether that's a dealbreaker for how you'd use it.

SplitWeb

Crop live web pages and tile them on one Mac screen

Crop live web pages and tile them on one Mac screen