Incompatibility with “Re-add text underline and justify” plugin?

I’m not familiar with that plugin, but you could add the underline and text justify with CSS.

Any text that you want to be underlined could be added with a CSS class, like this:
<p class="underline_this">UNDERLINED TEXT</p>

Then this CSS will make that text underlined:

.underline_this {
    text-decoration: underline;
}

You could do the same for the justified text, like this:
<p class="justify_this">UNDERLINED TEXT</p>

.justify_this {
    text-align: justify;
}

Does this work for you? You could also try following the instructions on the plugin page:

Select the Text which will be Justified, then press: SHIFT + ALT + J
SeIect the Text which wiII be underIined Press: CTRL + U

-Kevin

Yes, I ended up fixing it with CSS. It’s not ideal, but it will have to do until WordPress decides to reintroduce those buttons!

Thanks