[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 8.11.

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.