Congrats on mining a block!

You need to enable the coin control features in the options menu under wallet tab. Then when you send you need to select coin control features and select the coins that you allow to be used in the tx when sending.

You should do this before sending coin from a mining wallet all the time or you risk throwing away your potential hash power (Transactions).

You said you figured it out, just wanted to give a little more detail to help others out.