Change colour of Offset Preview

I can’t figure out where in the reporter’s script I can change the colour and alpha, currently it’s indistingguishable from the handle line.

Perhaps you want to try OffsetPreview.glyphsReporter.

Ooops, I thought that was the actual, show preview offset filter.
How do I create the filter for OffsetCurve, the following is not working:

Property:
Filter

Value:
OffsetCurve;11;10;1;0.5

I want it x:11, y:10, make stroke, 50%

Error:

Show OffsetCurve Parameter Preview plugin:
drawBackgroundForLayer_: 'objc.pyobjc_unicode' object is not callable

Oh, I need to take a look at the code again. Has not been in used or updated in ages.

Update: Fixed the bug mentioned above (and similar bugs in similar plugins on my GitHub). Please update.