From 6a4ede2495a830794ea85a7042d526c0357d528a Mon Sep 17 00:00:00 2001 From: Mitch-At-Work Date: Mon, 29 Sep 2025 14:47:26 -0700 Subject: [PATCH 1/2] Ignore IO buffer --- .../src/components/Virtualizer/useVirtualizer.ts | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/packages/react-virtualizer/src/components/Virtualizer/useVirtualizer.ts b/packages/react-virtualizer/src/components/Virtualizer/useVirtualizer.ts index 8940fc51..c26a8f6d 100644 --- a/packages/react-virtualizer/src/components/Virtualizer/useVirtualizer.ts +++ b/packages/react-virtualizer/src/components/Virtualizer/useVirtualizer.ts @@ -473,7 +473,7 @@ export function useVirtualizer_unstable( // Minus from original before position measurementPos -= overflowAmount; // Ignore buffer size (IO offset) - measurementPos += bufferSize; + measurementPos -= bufferSize; // Calculate how far past the window bounds we are (this will be zero if IO is within window) const hOverflow = latestEntry.boundingClientRect.bottom - From 3f089bc87bec0970362e79229e96c181a346d7ec Mon Sep 17 00:00:00 2001 From: Mitch-At-Work Date: Mon, 29 Sep 2025 14:48:03 -0700 Subject: [PATCH 2/2] Change files --- ...t-virtualizer-388fbe2c-fba9-42e7-8369-f6484974f821.json | 7 +++++++ 1 file changed, 7 insertions(+) create mode 100644 change/@fluentui-contrib-react-virtualizer-388fbe2c-fba9-42e7-8369-f6484974f821.json diff --git a/change/@fluentui-contrib-react-virtualizer-388fbe2c-fba9-42e7-8369-f6484974f821.json b/change/@fluentui-contrib-react-virtualizer-388fbe2c-fba9-42e7-8369-f6484974f821.json new file mode 100644 index 00000000..bc012097 --- /dev/null +++ b/change/@fluentui-contrib-react-virtualizer-388fbe2c-fba9-42e7-8369-f6484974f821.json @@ -0,0 +1,7 @@ +{ + "type": "patch", + "comment": "fix: Ensure IO buffer is ignored in the correct direction (remove, don't add)", + "packageName": "@fluentui-contrib/react-virtualizer", + "email": "mifraser@microsoft.com", + "dependentChangeType": "patch" +}