Superscript and subscript can be active at the same time (formatting conflict)

[cjung667]

In the text formatting (e.g. RTE/editor), “Superscript” and “Subscript” can be active at the same time.
Enabling one function does not disable the other, although only one of these two formatting options should be applied to a given character/selection at a time.

📝 Provide detailed reproduction steps (if any)

Type some text and select part of the text.
Click on “Superscript”.
Result: The selected text becomes superscript.
Without changing the selection, additionally click on “Subscript”.

✔️ Expected result

The new choice (Subscript) replaces the previous one (Superscript). The text is only subscript, not superscript anymore.

❌ Actual result

Both buttons can be active at the same time, leading to inconsistent formatting and potentially incorrect rendering in the editor/output.

❓ Possible solution

Perhaps a toogle could or a select field is possible

[Reinmar]

Thank you for reporting this.

There are actually legitimate use cases for nesting <sub> and <sup> — for example, isotope notation in chemistry (e.g. ¹⁴₆C, where mass number and atomic number are stacked beside the element symbol) or tensor index notation in physics (e.g. T^i_j). Nesting these elements is valid HTML, and to support wider content, we decided in the past not to make them mutually exclusive.

That said, you make a fair point — both Microsoft Word and Google Docs treat subscript and superscript as mutually exclusive formatting, and for most users this is the expected behavior. Applying both simultaneously is rarely intentional in typical editing scenarios.

We could make them mutually exclusive by default (toggling one disables the other), while providing a configuration option to allow nesting for users who need it. This way the default behavior matches what most people expect, while maintaining backward compatibility for those relying on the current behavior.

[Witoso]

Btw, congrats on the 20k issue spot! 🎉