tk-multi-workfiles2 Failed to create File Open dialog!

[nozongabriel]

Describe the bug
When using the Workfiles File Open the dialog never opens. in the log you can see:
[MSG][1276][sgtk.env.project.tk-substancedesigner]Detected std style sheet file '\VSERVER01\shotgun\NewTemplates2\install\app_store\tk-multi-workfiles2\v0.12.6\style.qss' - applying to widget <tank.platform.qt.tankqdialog.FileOpenForm_TkWidgetWrapper object at 0x000001AC629D98C8>
[ERR][1277][sgtk.env.project.tk-substancedesigner.tk-multi-workfiles2]Failed to create File Open dialog!

I had a little look in the tk-multi-workfiles2 but it didn't seem clear why it was erroring out

Thanks for the engine

To Reproduce
Shotgun => Shotgun Workfiles => File Open...

Expected behavior
A clear and concise description of what you expected to happen.
Dialog appears

Desktop

• OS: Windows 10
• Version Substance Designer 10.1.0 (also didn't work in the lastest 11.1.2)
• tk-multi-workfiles2 v0.12.6
• tk-core v0.19.18

Additional context
The other tools like workspace and the shotgun panel seem to work fine