ERIBAN  You cannot edit the color palettes from GrandPerspective. However, the color palettes are stored in the standard Mac color list file format so you can edit the palettes and add new ones using a color list editor that supports that format. An example is the ColorListEditor provided by Modesitt Software. Simply store the new palettes inside the GrandPerspective palettes folder (GrandPerspective.app/Contents/Resources/Palettes) and you can use the palette the next time you start the application.   
(Version 1.0)

ERIBAN  I am pretty confident that I found the bug that caused the crashes (basically, a silly typo). The fixed application can be (temporarily) found here as a release candidate:

http://grandperspectiv.sourceforge.net/ReleaseCandidates/GrandPerspective-0_9_13_1b2.app.zip

If it doesn't crash anymore on systems where it used to crash (please let me know), then it will be released officially tomorrow.  
(Version 0.9.13)

ERIBAN  I have hopefully found the cause of the crash, and fixed it in a release candidate that can (temporarily) be found here:

http://grandperspectiv.sourceforge.net/ReleaseCandidates/GrandPerspective-0_9_13_1b1.app.zip

I cannot reproduce the crash myself, so I would be grateful to hear whether or not this version does not crash anymore. If so, I will make it an official release. If not, I will continue my hunt for the bug.  
(Version 0.9.13)

ERIBAN  That looks like a useful extension of GrandPerspective. Adding support for Time Machine drives has been on my To Do list for a while, as I already imagined that GrandPerspective in its current form does not cope well with Time Machine. However, as I don't have access yet to a machine with Leopard/Time Machine, I have not yet been able to do so. So, thanks for filling the void in the meantime.

Cheers,

Erwin  
(Version 0.9.10)

ERIBAN  The next release of GrandPerspective will allow you to directly delete (i.e. move to Trash) files and folders from the application. Not sure though yet when it will be released, but hopefully not too long from now.  
(Version 0.9.10)

ERIBAN  There's even a reason for that, which I will let you figure out. :-)  
(Version 0.96)