Launcher output log area is much smaller than it was previously

The bug

The launcher's output log window displays the output in a much smaller are than it did previously. In older versions, the output filled the entire output log window, as shown in this screenshot taken in 2.2.2310:

However, in 2.2.2530, the output only fills the top portion of the output log window:

How to reproduce

1. Start Minecraft using 2.2.2530 (haven't tested on other operating systems)
2. View output log
   The output is only shown on the top portion of the output log window