I recently upgraded my organization's test Mediawiki installation to LTS version 1.35 in preparation of a similar upgrade on the production system. The upgrade was completed successfully, but I noticed a graphical problem with the sidebar after installing the Mediawiki 1.35 release of version 0.1.10 of the CollapsibleVector extension. After one of the test wiki authors confirmed the problem, further investigation showed that the sidebar displayed correctly with CollapsibleVector disabled.

The arrow that was previously shown beside each level one bullet and section header is no longer present, and instead a line is shown through each. The sections can be expanded and collapsed correctly, but the line is drawn through the section header when expanded, which does not appear to be intentional. This will also likely confuse the users of this wiki, as the arrow clearly communicated that a section is currently collapsed or expanded.

See the below screenshots for how each sidebar section is shown collapsed and expanded.

Reproduction

1. Install Mediawiki 1.35.0
2. Install CollapsibleVector version 0.1.10 for Mediawiki 1.35
3. View wiki page
4. Collapse and expand sidebar sections

Expected Behavior

• Sidebar sections begin collapsed with an arrow beside each level one bullet

Actual Behavior

• Sidebar sections begin collapsed with a line through each level one bullet