I doubt there will be any 100% foolproof way to support this—there are so many nuances to the button and input groups.

Would be fixed by: #11817

We used to have the font-size: 0; hack, but ran into issues of nested and custom content inheriting that. It require extra overrides to make it work.

What a custom content is in a input-group-btn?

@tlindig I'm not talking about v3 now—there's likely no problem there now. In v2.x we had issues though due to tooltip and popover placement. Custom content was the wrong term to use, also, so sorry for the confusion.

Either way, you are right, we need a better solution for this stuff. Looking into it now.

If font-size: 0 is not a possible solution, it would be more correct to say "do not use space character between elements in input-group-btn". But try to move over a space character, looks dirty IMHO.

Revisited and merged #11817. Thanks for hammering this home @tlindig—definitely an oversight on my part. Appreciate the attention to detail <3.

Wow, I am impressed. Respect!

Sorry, if I use to harsh words and that I spammed a little.