Overview:
When using the {{customText(255)}} configuration token in an Approved Email template, the input text field is not wide enough to see all of the text that is entered.
Root Cause:
This is working as designed. In Edit mode, the input text field is not wide enough to see all 255 characters that can be entered.
Solution:
The full text can be viewed by entering Preview mode. Use the Preview and Edit buttons to switch between Preview and Edit modes. The difference between Preview and Edit modes can be seen in the two pictures below.
Edit Mode:
Preview Mode: