Problems with the Members Plugin and permissions

I’ve created a new user role using the Members plugin but am getting strange behavior. If I check the “edit_posts” checkbox to allow this user to edit posts, they are not able to edit any web pages. I want this user to be able to edit all users pages and posts but limit their ability to change plugins, themes, etc. I can’t for the life of me figure out why this is not working correctly. If I set the user role to Editor, I get the same behavior. I was also using the User Role Editor at one point. Thought it might be a plugin issue so I changed it. Any help is appreciated.