The FILL BLOCK option is grayed out (both when I click on the EDIT button and when I Highlight and then click right button) and unavailable. Yes I am in Block Select Mode and have highlighted blank cells. This was one feature that appeared very useful to me. I had this same prob when I evaluated 6.3.1, never got it resolved and uninstalled Textpad. Heard there was a new version, so I down loaded version 7 today and same old stuff.
Try renaming your ConfigState.xml file. In Windows 7 it is located in
C:\Users\UserName\Application Data\Helios\TextPad\7
Exit from TextPad before renaming the file.