Redmine

Thank you for the patch!
This is something that has been bothering me as well — working with list items in CommonMark can feel a bit clumsy, especially when it comes to indentation.
At the same time, I agree that overriding the default Tab behavior is problematic, since users rely on it for normal form navigation.
To address this, the behavior has been adjusted so that Tab / Shift+Tab indentation is only triggered when there is a clear editing intent:

• Indentation is only applied when text is selected (selection present)
• Supports multi-line selections, allowing multiple list items to be indented/unindented at once
• When there is no selection, Tab retains its default browser behavior (focus moves to the next field)
• This avoids interfering with standard form navigation while still enabling efficient list editing

This approach follows patterns used in tools like GitHub, where structural editing is tied to active selection.

Florian Walchshofer

Thank you for the suggestion and the patch. I tried running the code, and it looks very good.

With the approach in your patch, since it does not interfere with the existing Tab navigation, I think we may not need to limit indentation only to list items. Markdown has syntax constructs other than lists that require indentation, so it would be useful if this feature could be used for those as well. For example: https://spec.commonmark.org/0.31.2/#example-254

I have attached my patch as 0002 in the format-patch series, on top of your patch. It applies indentation only to the selected text, without limiting the target to list items.

Setting the target version to 7.0.0.

Go MAEDA wrote in #note-7:

I found a strange behavior with this patch.

When the last character in the selection is a line-ending newline character, pressing Tab or Shift+Tab may indent or unindent lines outside the selection.

Steps to reproduce:

1. Enter two lines of text.
2. Move the cursor to the beginning of the first line.
3. Hold Shift and press the down arrow key to select the entire first line.
4. Press the Tab key.

In this case, only the first line should be indented. However, both the first and second lines are indented.

Could you please check whether the patch handles this case correctly?

Thank you for the feedback. I have attached a patch that fixes the problem.

Committed the patches with slight changes in r24719. Thank you for your contribution.

With this change, users can indent or unindent selected lines in a textarea using Tab and Shift+Tab, making it easier to edit nested lists and and other multi-line Markdown structures.