Text marking bug code viewer

[zTomz]

Existing issue?

• I checked the existing issues

What happened?

Expected vs actual result:

When I mark some text in the code view in the Flutter Gallery, the marked text and the indicators to move are not aligned. Better explanation in the screenshot I think:

I think, this only happens, when I mark text in free space. When I start with marking a word, this issue does not happen.

Steps to reproduce:

1. Go to Categories and choose any widget. For example Material and AppBar.
2. Go to the Code field and try marking a word in free space (where no word is).
   

Relevant log output

No response