After Effects - Can't Change Dash Option on a Stroke

Hi folks,

 I'm trying to create a path with the Pen Tool and turn it into a dashed one. I'm experiencing a missing settings field in the Dashes sub-option under Stroke. When I click on the arrow before "Dashes", nothing appears that you can tamper with as a setting.

I've recorded a short video of the problem. I've uploaded it here.

Does anyone have an idea why this might be happening?