bug(developer): A blank window tab appears when clicking the regression testing tab/options/edit regression test data. 

### Describe the bug

The "untitled" tab appears when editing the regression test data.
On the regression testing tab -> options -> edit regression testing data

### Reproduce the bug

I tested this issue with the attached "Keymandeveloper-18.0.86-Alpha" build on the Windows 10 & 11 OS environment: Here is my observation.

Steps to reproduce:

1. I installed the "keymandeveloper-18.0.81.exe" file.
2. Double-click on the "Keyman Developer" icon. The developer tool appeared correctly.
3. Open the Keyman keyboard project (*.kpj) file.
4. Open any keyman keyboard (*.kmn) file. (e.g., gff_amharic.kmn)
5. Navigate to the Debugger mode by pressing the F5 or (On build tab/Start Debugging).
6. Navigate to the layout tab. 
7. Navigate to the "Regression Testing" tab, and then click the "Start Log" button.
8. Click on an empty text box. Enter some letters, it's more than 10 letters.
9. Click the "Stop" log button.
10. Click the "Options" button, then select "Save Regression Test.".
11. Click the "Options" button, then select "Edit Regression Test Data.".
Actual Results: Here, an empty tab opened without any data. 
Please refer to the attached screenshot below

https://github.com/user-attachments/assets/4a51a90b-d02c-4eff-83d9-07715012ff83

### Expected behavior

_No response_

### Related issues

_No response_

### Keyman apps

- [ ] Keyman for Android
- [ ] Keyman for iPhone and iPad
- [ ] Keyman for Linux
- [ ] Keyman for macOS
- [ ] Keyman for Windows
- [X] Keyman Developer
- [ ] KeymanWeb
- [ ] Other - give details at bottom of form

### Keyman version

18.0.86 alpha

### Operating system

Windows 10 & 11 OS

### Device

_No response_

### Target application

_No response_

### Browser

_No response_

### Keyboard name

gff_amharic

### Keyboard version

_No response_

### Language name

_No response_

### Additional context

_No response_