In PDFCreator v2.2.1 (as well as the last few versions), under both fully updated Windows 10 Home and Windows 8.1, I believe that I have found a bug in connection with the setting:
"Profile Settings:Save:Skip print dialog (directly proceed to the save dialog)"
While this option is disabled (which I recall is the default setting), when the save dialog comes up, the filename is highlighted and the window has focus (pressing Home on keyboard places cursor at beginning of filename).
While this option is enabled, however, when the save dialog comes up, the filename is highlighted but the window is not in focus (one must click somewhere on the save dialog window to bring it into focus before pressing Home will place the cursor at the beginning of the filename).
I believe that in both scenarios, when the save dialog appears on the screen, it should be the window with active focus, allowing for immediate editing of the filename, and I do believe this would be a very easy fix.