Rounded corners not working

# Bug Report
Html doesnt support transparency
even with:
```
frame:false.
transparent:true
```

in settings file.

## Problem
Id like a fully transparent window but for some reason the background is always white.
Even with transparent set to `true`

### What is expected to happen?
Make window transparent.

### What does actually happen?
Its fully opaque with white

Start by reproducing the issue with the Electron settings file using frame:false and transparent:true, and confirm whether the window remains white. Investigate the window transparency behavior, then verify that the window background is transparent rather than opaque.

Written by the indexing model from the issue text.