Alright darn it, I'm admitting defeat again.
The windows forms designer will call BeginInit on controls while initializing them, but it casts to ISupportInitialize first.
(Control1 as ISupportInitialize).BeginInit();
However, there is no BeginInit on Control1, calling Control1.BeginInit fails.
I was under the impression that for Control1 to be able to support the interface ISupportInitialize, it would have to have the BeginInit method.