Go to https://nl.wikipedia.org/wiki/Lijst_van_rijksmonumenten_in_Zaandam?veaction=edit and double-click the table. The browser hangs while dealing with the fact that there are 87 templates (so probably double that number of parts, because there are whitespace-only content blocks in between).
And that's only 87 rows, https://nl.wikipedia.org/wiki/Lijst_van_rijksmonumenten_in_Alkmaar has 399 rows.
Version: unspecified
Severity: normal
| Status | Subtype | Assigned | Task | ||
|---|---|---|---|---|---|
| Duplicate | None | T71799 Editing a transclusion with many templates hangs the browser | |||
| Open | None | T134814 Multi-part transclusion dialog a little slow to load | |||
| Resolved | matmarex | T153475 Trying to scroll invisible elements into view is slow | |||
| Resolved | matmarex | T153490 Using $element.closest( 'html' ).length to check whether an element is attached is slow | |||
| Resolved | matmarex | T153713 TextInputWidget#adjustSize should do nothing if widget is detached | |||
| Resolved | matmarex | T154024 Kill slow MutationObserver stuff in TextInputWidget | |||
| Declined | None | T176998 Try using SentinelJS (or stealing code from it) instead of nasty code in TextInputWidget#installParentChangeDetector | |||
| Resolved | matmarex | T154025 Element#updateThemeClasses results in a separate setTimeout for each widget, which has some overhead, making it slow |
I can reproduce this in latest Chrome canary. The tab becomes entirely unresponsive.
Looking at the Chrome task manager I see the process is consuming 102% CPU and memory usage 520M and growing.
T134814 is a later duplicate of this task, but it has more interesting comments on it, so I'm duping this one.