When editing a simple line or simple fill symbol the outline options for line pattern only show solid. Debugging the SymbolStyler code reveals that an array of solid, dot, dash, dashdot, and dashdotdot should be added but something is going wrong and only solid gets displayed.
Thank you Robert,
I actually need to use the dijit in an application and not to just generate symbols. I'd like to use the OTB dijit so I don't have to spend time coding up everything from scratch.
Oh, I thought you were just looking to define symbol code. You will have to report this bug to esri tech support and see if it will get fixed in the next release.
I found if you change the css from claro to tundra (//js.arcgis.com/3.16/dijit/themes/tundra/tundra.css), the dropdown for the pattern works. It would be nice to fix in claro because the widget doesn't look that great with tundra. Also there are only a few of the line patterns available in the API in the widget.
I just noticed that the source code for the widgets are available: