#27672 makes it possible to select the display columns for the Gantt.
However, if you use MS Edge Legacy (old version), you can select columns, but only the default columns (Status, Priority, Assignee, Updated) are displayed and other selected columns (e.g. Spent time) are not displayed.

The following patch resolves this issue.

diff --git a/app/views/queries/_columns.html.erb b/app/views/queries/_columns.html.erb
index c5d14190e..18443de57 100644
--- a/app/views/queries/_columns.html.erb
+++ b/app/views/queries/_columns.html.erb
@@ -36,7 +36,7 @@
 <%= javascript_tag do %>
 $(document).ready(function(){
   $('.query-columns').closest('form').submit(function(){
-    $('#<%= selected_tag_id %> option').prop('selected', true);
+    $('#<%= selected_tag_id %> option:not(:disabled)').prop('selected', true);
   });
 });
 <% end %>