How to reproduce:
1. Open the attached "IN-144539" project
2. Open Window -> Sku Build Window
3. Click the "Export as arg string" button (or manually type/edit text into the TextField)
4. Click the generated text with your mouse multiple times (double-click / triple-click)
Actual result: Double-click and triple-click selection behaves inconsistently - not all lines are selected and in some cases nothing is selected at all
Expected result: Double-click selects the word, triple-click selects the full line/all text correctly every time
Reproducible with: 6000.0.0f1, 6000.0.76f1, 6000.3.17f1, 6000.4.10f1, 6000.5.0a1
Not reproducible with: 6000.5.0b11, 6000.6.0a6
fixed in: 6000.5.0a2
Reproducible on: macOS 26.5 (M1), Windows 11 (reported)
Not reproducible on: No other environments tested
Note: When the bug occurs, double-clicking and triple-clicking the text neither highlights nor selects it (confirmed via Ctrl+C - clipboard remains empty). This is not just a visual issue