The set attribute treats its value as a TextReference, which is ambiguous when a title contains !! or ##. The setTitle group names the target directly instead.

The attributes work together:

• setTitle is the tiddler to change, with no TextReference parsing
• setField is the field to write, defaulting to text
• setIndex writes a data index instead of a field
• setTo is the value to assign

Click a button to set the caption field, then watch it update below.