I realize the solution to this is to just not do it, but it took me a good hour to track down what was going on.
icon = 'shapes.dmi'
icon_state = "circle-filled"
filters += filter("drop_shadow", x=2, y=2, color="#000")
If you leave out the 'type=' before the type of filter you are creating, the project compiles fine, however when you try to run it, it fails silently. DS never appears, even in task manager. Running in DD seems to load up, but DS fails to connect and DD crashes silently.
Numbered Steps to Reproduce Problem:
1) Be an idiot.
Either a compiler error or an error message at runtime.
Don't be an idiot.