Change 403844 had a related patch set uploaded (by Mooeypoo; owner: Mooeypoo):
[mediawiki/extensions/Echo@master] Truncate page name in the sidebar and organize into table view

https://gerrit.wikimedia.org/r/403844

The patch above truncates correctly but it makes the sidebar a little less compact.

Before:

After:

I decreased spacing a bit and realigned the rows, but I also tried to make sure the lines are aligned to the middle of the cells, so the spacing is different a bit, but I actually think it makes it better now in the new version, showing everything aligned in the same line neatly. I couldn't get rid of more top/bottom spacing when it's table view, but it seems to be the "fault" of the icon that is now aligned to the middle of the line, and the counter that dictates the heights of each line. I could decrease the line-height in the counter, but then it makes the counter "box" less square, it doesn't seem to look that good.

@SBisson I think the new iteration in PS4 looks good, but there are still slight differences, so if you think the difference is significant, we can pass this through @Pginer-WMF

Here's the comparison of the new patch.

Before (master)

After

Change 403844 merged by jenkins-bot:
[mediawiki/extensions/Echo@master] Truncate page name in the sidebar and organize into table view

https://gerrit.wikimedia.org/r/403844

In T184143#3907760, @Mooeypoo wrote:

Here's the comparison of the new patch.

Checked in betalabs - the truncation of long titles looks good.