Re: On a bar appear the contents of a txt file

A simple solution would be *info expr(.myfunc(filename)) where myfunc returns the text in filename.  That could be a full path if the folder is not fixed in advance.
 

 This will cause the function to be called once per second per button to update the text with the current file contents  That might affect your computer's performance.  Or it might not, eg given that Windows will cache the file contents most of the time.  So I'd try that first.
 

 More complicated scripts would run from a file.watchfolder event which could be started by a Starup event for the bar which also initializes the text.  That works best if text files are in a fixed folder.
 

 Both cases would use manual button settings to size the button face so as to accommodate as much text as you want displayed.