When the BF editor is in split view mode and the editor background is dark, the separator line between the upper and lower split sections can be difficult to see. It would be helpful to be able to see this boundary clearly, as it is if the background is light. Perhaps a control over the color of this separator line would be appropriate.
The horizontal separator color is apparently tied to the gtk color scheme. If a "light" theme is chosen, the split view separator is clearly visible with a dark editor background. At 84, my vision isn't as clear as it once was, so I use a customized "dark" desktop theme which is much easier on my eyes.
Would it be possible to tie the split view separator color to it's own BF-configured, or per project color setting?