Be wary of "required" properties that must be explicitly set correctly in order for the object to function (especially if it's not obvious).
I recently got burned by this, and it's certainly a frustrating problem to diagnose. In my case, the function didn't give an error and just silently nop instead of doing the right thing. The docs were worthless, so I tried a few properties with promising names, but there were too many to find the right combo. I eventually searched around for a sample usage, saw the missing property, and got things working.
My plea to library designers: