macOS 15.5: White Flash When Closing Plugin Windows in Renoise 3.5.0 (Metal-related?)

Help, Support & Bugs
1

I’m seeing a brief white flash when closing plugin windows in Renoise 3.5.0 on macOS 15.5 (Sequoia). This happens with multiple VST3 plugins (tested UVI Falcon and Cherry Audio DCO-106), and appears regardless of sandboxing or Metal settings.

The issue seems to occur just as the plugin window is closed — a single frame of white before returning to Renoise’s UI. It does not happen in Logic Pro or Ableton Live, which also use Metal on macOS.

This could be related to how Renoise composites plugin windows or manages GPU draw calls.

While seemingly minor, it can have an outsized impact on accessibility — particularly for neurodivergent users or those with sensory sensitivity, where sudden visual flashes or visual instability can be uncomfortable or even triggering.

When I wrap a plugin in Blue Cat PatchWork, this issue doesn’t happen. However, the PatchWork window itself does have the white flash upon closure.

Here’s a short video demo of the issue:

[YouTube link]

System:

– Mac mini M2 Pro

– macOS 15.5

– Renoise 3.5.0

Let me know if I can provide logs or test anything further.

2

Just a quick update — I’ve started a new thread documenting a related, reproducible behavior with the Metal Based GFX Rendering setting that might be tied to the flash issue:

macOS 15.5: Reproducible Metal Rendering Toggle Flash with VST3 Plugins

This test shows the flash only starts after closing a VST3 plugin with Metal rendering OFF, and then toggling Metal back ON causes the entire UI to flash.

Might be the same root cause as the original issue here.