OS X leaks keyboard shortcut for optional button in dialogs

Hey, what’s up with my Tiger? I didn’t realized it all the last weeks but why there is no keyboard shortcut anymore to cancel a dialog? It was a fine thing to only have to hit the space key. I mainly used it within Lightroom to delete an image from the database. But as I see now, the button hasn’t a small blue border anymore. It’s cumbersome to grab the mouse and navigate to the cancel button.

Does anyone of you also have this problem? I could imagine that this regression was caused by the latest Apple update 2007-009 which also half-killed my OS X installation.

dialog

Update: The button I talked about isn’t cancel itself, sorry. What I mean is the optional button e.g. “Delete from Disk” within the following image:

Update 2: See comment 4 for the solution.