ScreenHaystack: Finding Blind Zones in GUI Grounding

Chenyue Li, Xiaoxiao Sun, Yubo Deng, Qinlin Zhao, Serena Yeung-Levy, Yuhui Zhang


Abstract
We introduce ScreenHaystack, a dynamic needle-in-a-haystack benchmark for evaluating spatial reliability in GUI grounding. Instead of testing each target at a fixed position, ScreenHaystack systematically relocates controlled target icons across high-resolution GUI backgrounds and measures whether models can localize them consistently. Using this benchmark, we find that leading GUI grounding models, including Qwen3-VL, UI-TARS, GTA, and UI-Venus, exhibit blind zones: spatial regions where grounding accuracy drops sharply despite fixed target appearance and instruction. These blind zones transfer to unseen ScreenSpot-Pro examples: targets inside blind zones are consistently harder to ground, with Qwen3-VL dropping by 16.1 percentage points, and controlled relocation shows that moving targets into blind zones decreases accuracy while moving them out improves accuracy. We further show through controlled synthetic experiments that uneven spatial coverage in training data can induce such blind zones. Therefore, we propose a simple strategy, blind-zone-oriented augmentation, which adds supervision in blind zones and improves ScreenSpot-Pro accuracy over both original and random augmented Click-100k fine-tuning.
Anthology ID:
2026.emnlp-main.904
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
20821–20838
Language:
URL:
https://aclanthology.org/2026.emnlp-main.904/
DOI:
Bibkey:
Cite (ACL):
Chenyue Li, Xiaoxiao Sun, Yubo Deng, Qinlin Zhao, Serena Yeung-Levy, and Yuhui Zhang. 2026. ScreenHaystack: Finding Blind Zones in GUI Grounding. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 20821–20838, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
ScreenHaystack: Finding Blind Zones in GUI Grounding (Li et al., EMNLP 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.emnlp-main.904.pdf