To reproduce:
1. Open a new project
2. Create a blend tree
3. Left click it
4. Notice that text in the preview window of the blend tree is unreadable

Note: on some layouts the text might be readable, but making the preview window smaller manually produces the same issue

Expected: text in the preview window of blend tree is readable no matter the size of the window
Actual: text in the preview window of blend tree is unreadable when the window is very small

Reproduced on: 5.5.0b8, 5.4.2f1, 5.3.6p7