Variable Default Value width changes when adding a new Variable to the Blackboard

Steps to reproduce:

1. Open the attached project
2. Open the New Graph.texmkr asset
3. In the Blackboard, expand the New Variable (1)
4. Press the + Button to add a new Variable
5. Observe the width of the New Variable (1) Default Value

Actual results: The width of the New Variable (1) Default Value shifts when creating new variables, causing visible flickering

Expected results: Creating new variables does not alter the size of existing Variable fields or cause Blackboard flicker

Reproducible with versions: 6000.5.0a5, 6000.5.0a6

Not reproducible with versions: 6000.4.0b7, 6000.5.0a4

Can’t test with versions: 6000.0.66f2, 6000.3.7f1 (Graph Toolkit not available as a built-in module)

Tested on (OS): Windows 11, macOS 26.2