Please make Modify>Expand/Contract available in Actions!

If you look closely in your movie, after you record your action the last step "Set Selection" of your action is selected. You hit play, and set selection removes your selection. You then hit play again, and there's no selection active, hence the expand step fails.

I'd also like to make a suggestion in process. You can modify the tools to do what you want without having to expand the selection or change layer selection each time to select and fill. My layer stack is similar to yours. A layer with painted lines. Dragging and dropping colors on the selections go to layers under the line drawing. See video:

I've attached a video and screenshot showing this error. Right now Adobe Photoshop has an error message whenever we try to put Expand in an Action file. I teach Digital Art at an arts school, and my students and I would really like this fixed during the next Photoshop update please! This would save us sooooo much time! Watch the video below and you will see the benefit of having it work! This would give us shortcuts of our shortcuts. I have contacted technical support several times about this issue but they send me to a link that does not work: http://feedback.photoshop.com

I hope someone on the Developer team will see this. I have devoted many hours to trying to get a Developer to see this.

Please upvote!