ID 249585 - Nuke Studio custom exporter bug in 10.5v1 due to API changes

Problem summary
API changes in 10.5v1 have caused custom exporters to no longer work/display in the contents tab

Customer reported version
nuke.10.5v1

Customer reported platform

Steps to reproduce
1) Go to https://github.com/antiero/dotStudio/tree/master/Python/Startup
2) Right-click and download ThumbnailExportTask.py and ThumbnailExportUI.py
3) Copy these .py files to ~/.nuke/Python/Startup
4) Launch Nuke Studio, create a sequence with some shots
5) Export the sequence, Process as Shots, create a new preset with Path: {shot}.png and Content set to Thumbnail Exporter.

Result: In the Content side, there are no custom UI controls shown
Expected: You should see controls for Frame Type, Size and File Type.

Workaround
Unknown.

Reproduced by support
Reproduced on:
OSX 10.11.3: Nuke 10.5v1
Windows 8: Nuke 10.5v1

Unable to reproduce on:
OSX 10.11.3:
Nuke 10.0v5
Nuke 10.0v4
Nuke 10.0v1
Nuke 9.0v1

Windows 8:
Nuke 10.0v4

Expected behaviour
For contents tab to display controls for Frame Type, Size and File Type.

Actual behaviour
Content tab in export window was blank