closes#12309
Fixes input elements becoming unusable due to drag selection preventing
default browser behavior.
**Problem:**
- Input elements couldn't receive focus because `event.preventDefault()`
was called unconditionally
- Removing `preventDefault()` broke click-outside-to-deselect
functionality
**Solution:**
- Only call `preventDefault()` when actually starting drag selection
- Preserves input focus while maintaining drag selection and deselection
behavior
**Changes:**
- Move `event.preventDefault()` inside the `shouldStartSelecting`
condition
- Update test to reflect correct behavior for disabled elements
78f8562457