Zotero 10.0.2 - High CPU Usage with PDF + Right Sidebar Open

chrisyeh96

I have the following Zotero setup:

MacBook Air M4 (24GB RAM), macOS 26.6.2
Zotero 10.0.2
All plug-ins disabled
~1500 items in My Library
~10 group libraries

Whenever I open any single PDF using Zotero's built-in PDF viewer, make the PDF tab active, and have the right-hand sidebar open, Zotero's CPU usage hovers around 65-70%, according to Activity Monitor. If the right-hand sidebar is closed, Zotero's CPU usage drops to 1-2%.

I am not doing anything else in Zotero. No scrolling, annotating, clicking. I just have the Zotero window open with 1 PDF tab active and the right sidebar open. It does not matter which of the right sidebar panels is active (i.e., Info, Abstract, Attachment, etc.). As long as the right sidebar is open, the CPU usage shoots up to 65-70%.

For comparison, here are the settings I tested:

BAD setting
- Active tab: PDF
- Other tabs: My Library
- Right sidebar: open
- CPU usage: 65-70%

OK setting
- Active tab: PDF
- Other tabs: My Library
- Right sidebar: closed
- CPU usage: 0.5-2%

OK setting:
- Active tab: My Library
- Other tabs: 1 PDF
- Right sidebar: open
- CPU usage: 0-2%

OK setting
- Active tab: My Library
- Other tabs: 1 PDF
- Right sidebar: closed
- CPU usage: 0-1%