TUI: Extra empty lines rendered alongside pink left border in prompt box [Mac Terminal only]

[mehfuzh]

In the terminal prompt box, there are additional empty lines rendered on the left side that display the pink border (border-left: tall #ec4899 on #prompt-container). These extra lines appear even when no text is entered, creating unnecessary vertical space in the prompt area.

Steps to Reproduce

1. Launch the TUI chat interface
2. Observe the prompt input area at the bottom of the screen
3. Notice extra blank lines on the left side carrying the pink border

Expected Behavior

The pink left border should only span the actual content area of the prompt box without extra empty
lines.

Actual Behavior

Additional empty lines appear alongside the pink left border, making the prompt area taller than
necessary.

Context

• The issue persists after adjusting padding on #prompt-container and padding-bottom / height on
  #prompt-box in tui/css/chat.tcss
• This may be related to how Textual's TextArea widget calculates its rendered height in combination
  with the container's border-left: tall style

https://github.com/smartloop-ai/smartloop/blob/main/tui/css/chat.tcss

[TomJGooding]

Could you provide a screenshot and/or ideally a minimal reproducible example?

[mehfuzh]

Thanks Tom for the pointer. Here is a sample project. In mac terminal, please run the following (you will need textual), I've copied the exact tcss from the main project:

./mre.sh

sl-mre-prompt.zip

Here is the output of the run:

It should just be a single line (here is a screenshot from my alacritty terminal)

I am wondering , if this is a specific case that needs to handled differently for mac terminal

Cheers
Mehfuz

[TomJGooding]

Thanks for the screenshots, I wasn't quite sure what you meant by "extra lines".

https://textual.textualize.io/FAQ/#why-doesnt-textual-look-good-on-macos

[mehfuzh]

I see interesting. Thanks for the pointer. I'll add to the known issues.