Redmine

One option to fix this is to display the watchers on the same line delimited by comma in the same way we display subprojects in project overview.

Marius BĂLTEANU wrote in #note-2:

One option to fix this is to display the watchers on the same line delimited by comma in the same way we display subprojects in project overview.

I confirmed that the issue was resolved by the 43004-fix-for-watchers-in-gantt.patch changes.

As a suggestion, how about applying the following change in addition to the patch from 43004-fix-for-watchers-in-gantt.patch?
This makes the behavior more consistent when resizing the column width. Of course, feel free to ignore this if it's out of scope for the current patch.

diff --git a/app/assets/stylesheets/application.css b/app/assets/stylesheets/application.css
index 0185ef771..088f5a00e 100644
--- a/app/assets/stylesheets/application.css
+++ b/app/assets/stylesheets/application.css
@@ -1825,7 +1825,7 @@ td.gantt_watcher_users_column div.issue_watcher_users ul {
 }

 td.gantt_watcher_users_column div.issue_watcher_users ul li {
-  float: left;
+  display: inline;
 }

 td.gantt_watcher_users_column div.issue_watcher_users ul li:not(:last-child)::after {

Committed the fix with the change proposed by Mizuki, thanks!