Also, another question related to column icons. In an advanced rule, what is the most correct way to return no icon?
Example: My 'Cleanup' VL also searches for marked:true books.
Code:
program:
first_non_empty(
[lots of entries for specific metadata issues]
## Fallback
if is_marked() then ' ' fi,
if 'Cleanup' inlist virtual_libraries() then 'polish.png' fi
)
If I use
'' (no space), it returns 'polish.png' for marked books. Hence the whitespace.