fix(tui): avoid overlay scrollback inflation on widen

packages/tui/CHANGELOG.md

@@ -6,6 +6,7 @@
 
 - Fixed markdown H1 headings ending with inline code from leaking underline styling into trailing line padding
 - Fixed slash-command argument autocomplete to await async `getArgumentCompletions()` results and ignore invalid return values, preventing crashes when extension commands provide asynchronous completions ([#2719](https://github.com/badlogic/pi-mono/issues/2719))
+- Fixed non-capturing overlay padding from inflating scrollback and corrupting the viewport on terminal widen ([#2758](https://github.com/badlogic/pi-mono/pull/2758) by [@dotBeeps](https://github.com/dotBeeps))
 
 ## [0.64.0] - 2026-03-29
 

packages/tui/src/tui.ts

@@ -722,9 +722,10 @@ export class TUI extends Container {
 			minLinesNeeded = Math.max(minLinesNeeded, row + overlayLines.length);
 		}
 
-		// Ensure result covers the terminal working area to keep overlay positioning stable across resizes.
-		// maxLinesRendered can exceed current content length after a shrink; pad to keep viewportStart consistent.
-		const workingHeight = Math.max(this.maxLinesRendered, minLinesNeeded);
+		// Pad to at least terminal height so overlays have screen-relative positions.
+		// Excludes maxLinesRendered: the historical high-water mark caused self-reinforcing
+		// inflation that pushed content into scrollback on terminal widen.
+		const workingHeight = Math.max(result.length, termHeight, minLinesNeeded);
 
 		// Extend result with empty lines if content is too short for overlay placement or working area
 		while (result.length < workingHeight) {