tested on win-xp and os-x both with 154:

create a new sketch, write something in it, press save, dialog opens, choose a location, click
"ok". now you're back in processing and it says "Save Cancled." in the status bar, the sketch
still being in the temporary folder and marked modified.

i found the problem:

in Sketch.java on line 743:

if (newName.equals(oldName)) {
return false; // Can't save a sketch over itself
}

the if-clause will be true for new unsafed sketches if they are not renamed in the dialog.

fixed for 0155, please test the svn to make sure no other regressions are
introduced.