A 20-year-old HCI paper, resurrected as a Chrome extension

I missed the tiny "x" on a browser tab again today. Meant to close it, switched to it instead. Aiming a one-pixel pointer at an eleven-pixel checkbox is basically microsurgery, and somewhere along the way we all just accepted that. Here's the strange part: HCI research solved this twenty years ago. It just never shipped. The paper In 2005, Grossman and Balakrishnan published The Bubble Cursor at CHI. The whole idea fits in one sentence: Make the cursor's hit area a dynamic circle that always contains exactly one target. That turns out to be the same thing as always selecting the target nearest to the pointer. Picture the screen divided into Voronoi cells, one per clickable thing, and the cursor picking the owner of whatever cell it's currently in. The clever part is what it refuses to do. Naive "gravity" cursors snap to every link on the way to the one you actually want, and they get stuck. The bubble cursor grabs exactly one target by definition. The moment a second target becomes nearer, it switches. So it stays calm on link-dense pages, and the paper showed significant speedups in controlled experiments. Twenty years later our cursors are still naked, so I built it as a Chrome extension. It's called MagPoint . The core is about 30 lines A content script collects clickable elements ( a[href] , button , input , ARIA roles and so on) and, every frame, picks the one with the smallest point-to-rectangle distance: function pointToRect ( x : number , y : number , r : DOMRect ): number { const dx = Math . max ( r . left - x , 0 , x - r . right ); const dy = Math . max ( r . top - y , 0 , y - r . bottom ); return Math . hypot ( dx , dy ); } Clicks that land in the empty space near a captured element get re-routed to it. Past a max radius of 120px the magnet lets go, and empty-space clicks behave like the normal web. It also stands down while you type or select text, because getting yanked toward a link mid-sentence would be infuriating. The rule that kept me sane: the vis