PsychoPy Version

2026.1.1

What OS are your PsychoPy running on?

macOS Silicon

Bug Description

When creating a MovieStim without an explicit size argument, it produces an error "TypeError: 'NoneType' object is not subscriptable" at this point in the MovieStim code (line 1267-1270 in current version):

 if value[0] is None and value[1] is None:
        # if both values are none, use original size
        value = layout.Size(self.frameSize, units="pix", win=self.win)

Expected Behaviour

Default size should be automatically extracted on load, or there should be a functional default value.

Steps to Reproduce

Create MovieStim object without explicit size argument.

Additional context

This was introduced in #7325 and has been present since 2025.2