Keeping track of changes to a program (version). 
Making sure that every change is tested (validation). 

Implementation

• Each word carries a timestamp, which is displayed in the WORD list. 
   
• The timestamp is updated whenever the word's definition is edited. 
   
• You can enter a version number in the system menu (Ctrl+Sft+F3). 
  The version is displayed with the program name on the lower frame line. 
   
• HolonX stores the time and date of the change of the version number. Thus the words which are changed in the new version have a timestamp later than the version timestamp.
    
• The color of the date in the WORD list indicates the validation level. 
    
• The date is red if the definition has been edited.
    
• The date is blue if the word has been loaded, that is: the changed word has been written to the text file and presumably also been converted to code in the external interpreter/compiler. Thus blue words are (believed to be) ready for testing. 
    
• The date is green for validated words.  If the test is positive and you are sure that the word is ok, validate the word with the command F6=Valid. 
    
• The date is grey for words that have been validated in the previous version(s) and have not been touched in the new version.

Result

The changed words are clearly visible in the browser. If all dates are either green or grey, the new version is finished.

I welcome your comments. It this practical? Would you use it?