Lets take a look at one of the trransactions for that address in BC.info:
https://blockchain.info/tx/e37923bc171f74b7bf43ee2c22ed260b80f23b59f9ca38320973f7a73bbc1793So what happened is, 15BTC was sent to 1LAdprC8a2Y2JrB3qRvEQsX68nZUHC6Nax. Then the owner sent 10BTC to 1LBrdEQgvgxbtaP6ameij3AR1yDoEMYR2U and the remaining amount (after tx fee) 4.995BTC was sent to one of the owners change addresses 1Mt84HnC635ebTWyu73dfMFtQqEsUQr65b
When you send BTC, you are basically spending a transaction that somebody else sent you, and you have to spend ALL of it, so to add anonymity, the change from each new transaction is sent to a new address.
Why aren't they displayed in the UI? No idea, they are displayed in most BTC clients, just not the original for some reason.