[chaley]

This feature has a small bug in calibre 8.10.0 where the first time one defines a custom tooltip for a column, calibre must be restarted to "see" it. Subsequence edits of the tooltip for that column don't require the restart. The fix is in calibre source and will be in the next release/preview.

Here is a basic example of using a custom tooltip: presenting a list of genres in a more readable fashion.

The standard tooltip looks like this. There are multiple genres per line with some of them broken across lines.


If I use this template to generate the tooltip

program: 
	res = 'Genres:';
	vals = list_sort($#genre, 0, ',');
	for t in vals:
		res = res & '<br>' & t
	rof;
	res

then I see


And yes, the genres don't make a lot of sense.