Critical rendering issue in Candle 10+ (Qt 5.15) on Windows 7 with Intel HD Graphics

[DS-Pro]

Versions

• Candle version: 10.11.1, 11.2
• Firmware version: 1.1f

PC info

• OS: Win7
• OpenGL version: 4.0 (Intel HD Graphics, driver 9.17.10.3347)

Describe the bug
Critical rendering issue in Qt 5.15 applications on Windows 7
When launching the application on Windows 7, the main window opens but its content area (frames) remains completely blank/white. However, UI elements that use native Windows rendering (menus, configuration dialogs, popup windows) display correctly.
The issue appears to be related to the graphics backend selection in Qt 5.15.
The application works perfectly when forced to use Desktop OpenGL (QT_OPENGL=desktop) but fails with the default backend.

To Reproduce
Steps to reproduce the behavior:

1. Run Candle 10 or 11 on Win7 with Intel HD Graphics
2. See error

Expected behavior
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Screenshots
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Example files
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Additional context

Technical details:
This is a known issue in Qt 5.15+ on Windows 7 - Qt's ANGLE backend (DirectX translation layer) fails to initialize properly on some Windows 7 configurations. The problem occurs because newer Qt versions prioritize ANGLE over Desktop OpenGL.
Qt 5.5 used OpenGL 2.x successfully on the same hardware.
Related Qt bug reports confirm similar issues with Qt 5.15.9/5.15.10 on Windows 7.
Setting QT_OPENGL=desktop provides a working workaround.

Workaround for users:
Create a batch file to launch the application:

@echo off
set QT_OPENGL=desktop
start candle.exe