Slow Loading and Incorrect Previews in Presentation Viewer

Hello PA Team,

I'd like to report a performance and rendering issue with slide previews in the Presentation viewer.

The Issue:
When opening a Presentation, the slide previews (thumbnails) often take an excessive amount of time to load (40+ seconds).

Observed Symptoms:

1. Grey Placeholders: Users see grey boxes instead of slide previews for a long time.

2. Stale/Incorrect Images: Sometimes, the viewer initially displays thumbnails from a previously opened presentation before eventually updating to the correct ones. This is very confusing for users.

Impact:
This significantly degrades the user experience. Users are left waiting or are misled by incorrect thumbnails, making navigation difficult.

Expected Behavior:
Slide previews should load reasonably quickly. If loading takes time, a proper loading indicator should be shown, and the system should never display cached thumbnails from a different presentation.

Screenshots:

• Screenshot 1: Grey placeholders (loading state). 

  

• Screenshot 2: Correct previews (after ~40 seconds).

  

  Please investigate the performance of the thumbnail generation/caching mechanism.

Thanks.