expand min-height-window size

to make minHeight covers the dialogs.
@devoncarew

Before
![image](https://f.cloud.github.com/assets/756988/2438955/1c96e270-adf8-11e3-812e-9705d82c92a1.png)

After
![image](https://f.cloud.github.com/assets/756988/2438958/213df53e-adf8-11e3-93ea-d265c654a449.png)