Repro steps:
1. Open Particles scene from attached project.
2. Select particle system and click on any curve (i.e. turn Start Lifetime to a curve and select it).
3. In the curve system, try to select the number in the upper-left corner.
4. Observe how the number does not appear to be selected.
5. Type a new number in.
6. Number changes.

Expected outcome: To be able to highlight the number field and view the text cursor's position.

Notes:
- Regression: appears first in 5.4.0b3
- Though the text field is not highlighted, typing values in does work.