Labels on buttons

Skype, from www.skype.com is a fantastic piece of technology. Free peer-to-peer internet telephony with high call completion and excellent audio quality. The application also features instant messaging and file transfer capabilities.

When transferring a file across Skype from one client to another, a pane is displayed on the screen to tell the user what is happening. The user accepts or denies the incoming file, and selects a point to save the file to if desired.

Once the file has finished transferring two buttons appear at the bottom of the pane - one labelled 'Open' and the other labelled 'Close'.

Any guesses as to what these buttons do?

It turns out that the 'Open' button does the equivalent of double-clicking the file to display it on screen or load it into an editor etc. By that reasoning, 'Close' should surely close the file?

No, instead the 'Close' button closes the file transfer window.

A simple example but one that needs to be made - careful labelling of buttons is of paramount importance. It would cost nothing to rename the buttons as 'Open File' and 'Close Window'.

Then again, why is a button for 'Close window' needed at all when the window has a perfectly good close icon in the window furniture?