GUI grounding requires locating small controls in cluttered screenshots and identifying which control a natural-language instruction refers to. Cropping and enlargement can expose local detail, but the resulting image may still leave ambiguity about the intended target. We propose PreView, an auxiliary preprocessor that improves the inputs to an existing grounding model without further training that model. PreView prepares two complementary types of input features: task-relevant views for localization and candidate-specific cues for target understanding. A trained lightweight auxiliary model predicts and refines a center, crops the screenshot into a local view, and enlarges that view for zoomed-in grounding. It also prepares a visual cue (i.e., a red-circle marker with a location hint) and a textual cue describing the candidate's identity or function. The frozen grounding model uses the prepared inputs to predict the final click. Across five benchmarks, PreView improves the average grounding accuracy of Qwen3-VL-2B, OS-Atlas-4B, and Qwen3-VL-4B without further training these grounding models. Extensive analyses examine the contributions of views and cues, center refinement, and visual input budgets.
Figures & tables
Figure 1: PreView prepares views and cues at the input level, without modifying the grounding model or accessing its internal states.
Figure 2: Overview of PreView . For localization, the auxiliary model refines the initial center c1 into c2 to prepare a task-relevant view through cropping and enlargement. For understanding, it provides a visual marker with a location hint and generates a candidate description. The frozen grounding model uses the prepared view, instruction, and available cues in a single call. The predicted click is then mapped back to the original screenshot.
Model
SSPro
OSW-G O
OSW-G R
MMB-GUI
SSv2
UI-V
Avg.
≤3 B
UI-R1-E-3B
33.5
–
48.8
68.4
88.6
16.5
–
SE-GUI-3B
35.9
–
46.1
66.3
86.8
15.0
50.0
InfiGUI-R1-3B
35.7
–
42.9
70.6
89.5
17.8
51.3
GUI-G 2 -3B
36.4
–
53.5
66.3
87.6
18.7
52.5
GUI-G1-3B
37.1
–
49.5
71.0
89.5
20.3
53.5
Table 1: Grounding accuracy (%) by model size. O and R denote original and refined OSW-G instructions, respectively. Bold marks PreView scores that are column-best within each size group. Δ denotes percentage-point gains. ∗ marks our SSPro evaluations. – indicates unavailable or unverified scores. Reference averages follow GroundCUA. Our five-benchmark averages use OSW-G R .
Hyperparameter
Value
Epochs / precision
2 / BF16
Optimizer
AdamW
Learning rate
5×10−5
Weight decay
10−3
LR schedule / warmup
Linear / 3%
Micro / effective batch size
4 / 128
Table 2: Auxiliary-model training configuration.
Method
Grounding model
Base
Enhanced
Δ
ReGround
OS-Atlas-7B
18.9
40.2
+21.3
ScreenSeekeR
OS-Atlas-7B
18.9
48.1
+29.2
RegionFocus
Qwen2.5-VL-7B
26.8
32.1
+5.3
ZoomClick
UI-Venus-7B
50.3
65.7
+15.4
UI-Zoomer
UI-Venus-7B
50.0
61.8
+11.8
AutoFocus
UI-Venus-7B
50.3
67.8
+17.5
Table 3: Comparison with training-free methods on SSPro. The Base and Enhanced columns show accuracy (%). Δ is the gain in percentage points.
Figure 3: Auxiliary-model direct hit (a) and center containment (b). Initial, Refine 1, and Refine 2 correspond to c1 , c2 , and c3 , respectively.
Direct hit (%)
Benchmark
Accept
Reject
NReject
SSPro
62.0
18.6
295
OSW-G R
77.2
25.4
71
MMB-GUI
82.0
41.3
625
SSv2
90.0
63.4
344
UI-V
49.6
12.8
1520
Table 4: Auxiliary-model direct hit by verification response, on target-present examples. Weighted Avg. weights each benchmark by its accepted or rejected sample count for the corresponding column.
Model
Input
Visual Cue
Textual Cue
SSPro
OSW-G O
OSW-G R
MMB-GUI
SSv2
UI-V
Avg.
Qwen3-VL-2B
Full
–
–
43.1
46.1
62.1
72.9
91.4
16.5
57.2
View
–
–
56.9
52.7
66.3
75.7
84.8
26.0
61.9
View
✓
–
55.6
54.8
65.8
76.4
85.2
32.7
63.1
View
✓
✓
59.3
55.0
66.8
77.0
86.0
33.7
64.6
OS-Atlas-4B
Full
–
–
2.8
10.5
8.5
26.6
62.7
7.3
21.6
View
–
–
21.7
27.1
24.1
37.8
63.0
13.0
31.9
Table 5: View and cue ablation (accuracy, %). Full uses the original screenshot. Avg. uses OSW-G R .
Figure 4: Effects of cropping area and enlargement on Qwen3-VL-2B at different visual budgets.
Figure 5: Cue recovery and regression under correct and incorrect cue locations for Qwen3-VL-2B.
Benchmark
Full
View
SSPro
52.9
59.0↑
OSW-G O
56.2
57.6↑
OSW-G R
67.7
68.3↑
MMB-GUI
81.1
76.9↓
SSv2
90.4
81.8↓
UI-V
60.3
54.5↓
Table 6: GroundNext-7B with View (accuracy, %). Arrows compare with Full.
Appendix figures & tables6 assets
Supplementary material from the paper’s appendix.
Appendix
Benchmark
Samples
SSPro
1,581
OSW-G R
564
MMB-GUI
3,594
SSv2
1,272
UI-V
5,479
Appendix
Table 7: Sample counts for the evaluation benchmarks.
Qwen3-VL-2B
Qwen3-VL-4B
Category
N
Full
PreView
Full
PreView
Basic
1772
23.8
43.8
33.5
49.6
Functional
1772
21.5
41.8
31.5
47.5
Spatial
1935
5.3
17.0
12.0
26.0
Text
980
42.6
61.2
54.1
69.7
Icon
4499
10.9
27.7
19.0
34.2
Appendix
Table 8: UI-V results by instruction and element type.
Qwen3-VL-2B
Qwen3-VL-4B
Category
N
Full
PreView
Full
PreView
CAD/Text
197
32.0
61.4
59.9
68.0
CAD/Icon
64
18.8
28.1
20.3
32.8
Dev/Text
154
64.3
74.0
81.8
78.6
Dev/Icon
145
13.1
37.2
34.5
40.0
Creative/Text
198
57.6
67.7
71.2
71.7
Appendix
Table 9: SSPro results by application domain and element type.
Qwen3-VL-2B
Qwen3-VL-4B
Category
N
Full
PreView
Full
PreView
Text Matching
261
74.7
73.2
81.2
78.5
Element recognition
330
66.1
72.7
73.3
75.5
Layout understanding
253
71.9
74.3
76.7
79.4
Fine-grained manipulation
152
48.7
52.0
62.5
59.9
Refusal bucket
9
0.0
0.0
22.2
0.0
Appendix
Table 10: OSW-G R results by task type.
Qwen3-VL-2B
Qwen3-VL-4B
Category
N
Full
PreView
Full
PreView
Windows/Basic
271
80.4
87.8
86.3
90.4
Windows/Adv
272
45.6
52.6
68.0
59.9
macOS/Basic
345
78.0
87.8
90.4
89.9
macOS/Adv
346
50.3
61.6
73.1
68.5
Linux/Basic
191
66.0
75.4
79.6
77.0
Appendix
Table 11: MMB-GUI results by platform and difficulty.
Figure 6: Successful corrections and failure cases of view and cue preprocessing for Qwen3-VL-2B.