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Also notice that some translations not being applied to the forum bottom box that are applied on the statistics block. Now to read up on how to change the names of the catalogue fields themselves, so name is translated.

It's intentional. I'm adding this to the docs...

The default CSS will have provisions to cope with translations. For example, we only have fixed layout for tables on English as we can't trust name lengths on other languages to not overrun:
[code]
.wide_table {
width: 100%;
/*{+START,IF,{$EQ,{$LANG},EN}}*/
table-layout: fixed;
/*{+END}*/
}
[/code]
If you like you can just change it to:
[code]
.wide_table {
width: 100%;
table-layout: fixed;
}
[/code]
and make sure your language strings don't overrun.

"Also notice that some translations not being applied to the forum bottom box that are applied on the statistics block."

These are different language strings I think. The one's in the side block are standalone labels, the others combine the label and count together into more of a phrase.

"Now to read up on how to change the names of the catalogue fields themselves, so name is translated."

Same as translating any content - edit in the language you want it to be different in.

That change works fine on Catalogues and the Forum Bottom Bar, but it sets the Topic and Posts columns of the forum to be 25% each of the width in both German and French.

(Click to enlarge)

I doubt it.
I suspect what you're seeing is nothing to do with that, and to do with some other CSS differences for non-English languages.

This is in cns.css...

/*{+START,IF,{$EQ,{$LANG},EN}}*/
.cns_forum_topic_wrapper_column_column2, .cns_forum_grouping_column2 {
width: 100%;
}

.cns_forum_topic_wrapper_column_column3 {
word-wrap: break-word;
width: 100px;
}

.cns_forum_topic_wrapper_column_column4, .cns_forum_grouping_column3 {
word-wrap: break-word;
width: 5em;
}

.cns_forum_topic_wrapper_column_column5, .cns_forum_grouping_column4 {
word-wrap: break-word;
width: 5em;
}

.cns_forum_topic_wrapper_column_column6 {
width: 14em;
}

.cns_forum_topic_wrapper_column_column6_shorter {
width: 9em;
}
/*{+END}*/


i.e. we only set the column widths for English.

For non-English they will set based on content. If there aren't long forum names or topic names, it's going to divide the space more equally.

I don't think there's a lot we can do about this. We can't predict if the title "Topics" is going to take a few characters, or 50 characters - it depends on the language. And if it does take 50, we'd want the browser to then wrap it intelligently.