**System Information**
Operating system: Linux-5.10.0-3-amd64-x86_64-with-glibc2.31 64 Bits
Graphics card: RTX 3070 460.56
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: RTX 3070 461.72
**Blender Version:**
Broken: 2.91 release, 2.92 release, 2.93.0 Alpha `rB70e73974b593` 2021-03-10 04:47
Worked: 2.90 and below
**Short description of error:**
Ever since Blender 2.91 I have experienced this bug where certain aspects of the UI will change colour on occasion. The areas I've seen this issue occur the most are high lighted in the image below.
{F9882491}
This flickering seems to occur when two parts of the UI are being updated at the same time? I'm not really sure. The bug seems to occur during a change somewhere in the UI (Clicking on a box, deselecting a bunch of objects, etc), but the same actions don't always trigger this bug. There can even be long stretches of time where this bug does not occur. Hence why I have not reported it, as I've had a hard time finding a reliable way to reproduce it. However, I have found a way to reliably reproduce this issue. It can be done with a third party add-on (shown in the two videos below) or with Blender with factory defaults (as shown in the steps below)
Here's some videos showing off the issue.
This is the area where the bug occurs in the video:
{F9882527}
|{F9882499}|{F9882505}|
|Linux (GPU rendering)|Windows (GPU rendering)|
I have done three tests (Linux with GPU rendering, Linux with Software Rendering, Windows with GPU rendering) because at first I thought this might be an issue with my Linux installation or the drivers I have. So after testing Linux with GPU rendering, I tested Software Rendering, and that shows the issue, suggesting the issue isn't the GPU driver. Then I tested Windows just to make sure it's not a Linux thing, and seeing the issue show up on Windows shows it's not a Linux thing.
**Exact steps for others to reproduce the error:**
**Unreliable method:**
1. Use Blender for an extended period of time. At some point you may bump into this issue.
Reliable method: (for me at least)
1. In a new file, change the render engine to Cycles and select GPU compute.
2. Disable viewport overlays in the 3D viewport.
3. Split the 3D viewport in two and change one of them to a shader editor
4. Entered rendered view in the 3D viewport.
5. Adjust numerical render settings that affect Cycles rendering, causing a viewport refresh. The way you adjust these numbers is you click on it (allowing you to type in a number), then move your mouse to another input field, input a value, and press enter. (In my case, I used AO distance in the `Fast GI Approximation` section of the `Light Paths` panel of `Render properties`).
This change in colour in the UI will be found in the shader editor here:
{F9930022}
Here's a video demonstrating it:
{F9930020}
---
**Old method: Do not use.**
> **Reliable method (for me - same as videos above):**
> 1. Install the `Scatter` add-on by BD3D (https://blendermarket.com/products/scatter). Sorry, it costs money. There are probably other add-ons similar to this one that would allow the easy reproduction of this bug.
> 2. Open up a shader editor beside the 3D viewport.
> 3. Open the "Properties Panel" in the 3D viewport with `N`, switch to the `Scatter` tab and hover your mouse over the `Image area` and you should see this bug.
>
> Note: I only got the `Scatter` add-on **yesterday (as of the time of writing)**. I have been experiencing this bug for a few months. The `Scatter` add-on is not the cause (or I don't believe). During the past few months without the `Scatter` add-on, I did not have any other add-ons installed (outside of the defaults like Cycles). So I do not believe add-ons are the cause.