Dragging selector from selector row background shows preview but does not apply class in UI Builder

Steps to reproduce:

1. Create a new project using Universal 3D template
2. Go to Assets > Create > UI Toolkit > UI Document (UXML)
3. Open the created .uxml asset in UI Builder
4. Add a Visual Element to the Hierarchy
5. Add a new selector  (e.g. ".test") with a StylesSheet in UI Builder
6. Click the empty space to the right of the selector label and drag it onto the VisualElement
7. Observe the behavior

Actual results: A drag preview appears (selector text shown in white), but dropping it onto the VisualElement does not apply the selector/class

Expected results: Dragging the selector from anywhere within the selector row should apply the selector to the Visual Element when dropped, the same way as when dragging directly from the selector label

Reproducible with versions: 6000.0.71f1, 6000.3.8f1, 6000.4.1f1, 6000.5.0b1, 6000.6.0a1

Tested on (OS): macOS 26.3 (M1)

Notes:

• The entire selector row highlights when selected, which visually suggests the whole row is interactive and draggable, creating UX inconsistancy
• It is easy to slightly misclick next to the selector label when attempting to drag it, which results in the selector not being applied
• Dragging directly from the selector label (e.g. ".test") works correctly and applies the class to the VisualElement
• Dragging from the empty space to the right of the selector label shows a drag preview but the drop operation has no effect, while dragging from the left has no effect/highlight - I feel like the behavior should be consistant from both sides