Can't load any SLANG shader preset from QT interface

First and foremost consider this:

• Only RetroArch bugs should be filed here. Not core bugs or game bugs
• This is not a forum or a help section, this is strictly developer oriented

Description

Can't load any SLANG shader preset from QT interface

Expected behavior

Shader preset should load into window.

Actual behavior

Nothing happened, shader window stays without any shaders.

Steps to reproduce the bug

1. Load Retroarch
2. Switch video driver to "glcore"
3. Restart Retroarch.
4. Open Desktop QT UI.
5. Go to shaders.
6. Open any preset, for example, "mdapt.slangp"
7. Nothing happened, In console window shows message:

[INFO] [Qt]: Reloading shader parameters.

Bisect Results

[Try to bisect and tell us when this started happening]

Version/Commit

You can find this information under Information/System Information

• RetroArch: 6df4e7778f

Environment information

• OS: Windows 8.1 Enterprise x64
• Compiler:

No source file or test is named. First reproduce the issue in RetroArch's Desktop QT UI using the glcore video driver and mdapt.slangp; investigate the shader-preset loading path, and consider the work complete when the preset loads and appears in the shader window without the reported failure.