When I try to send coin on multibit, the send button is greyed out and I cant click it. What gives? My coins are confirmed.
Like all the Bitcoin clients, MultiBit is like a duck paddling on a lake. On the surface everything is calm but the legs underwater are kicking continuously. There is a lot of activity under the surface talking to the network, updating and saving the wallet etc.
The Send bitcoin button is greyed out when the client is either busy, or waiting for something else to complete. If you hover over the button with your mouse the tooltip normally gives you more information.
The possible reasons are:
1) If you are performing an operation that affects the structure of the wallet, various options (including Send bitcoin) are temporarily disabled. This is: add/ change/ remove password, add receiving addresses, import/ export private keys, reset blockchain.
2) MultiBit transmits the signed transactions on one bitcoind connection and listens on its other bitcoind connections to hear the transaction coming back. (It then knows the transaction is in the Bitcoin network and propagating). For this reason, it waits until it has two bitcoind connections before enabling the Send button. You should see a message on the Send window to this effect if this is happening. If you did something fancy with your network connections, for instance only opened port 8333 to a single node, you might have inadvertently prevented MultiBit from making multiple bitcoind connections and would see this.