Hello,
I was very unhappy what to do, why the Tracks Manager shows only about 1/5 of all songs that I have in the database. I have done everything, I was trying to remove some special characters, rewrite subcategories in the database, I made several times new database etc...

... and finally.... I found the problem! :-)
There is a big bug in the filtering option for Enabled / Disabled / Show All songs. The option Show All shows both, enabled and disabled songs together, but only up to the count of enabled songs in the database.
So for example: I have 10500 songs and only 2600 songs enabled, the rest is disabled.
- Choosing the option "Enabled", shows all 2600 enabled songs absolutely correctly
- Choosing the option "Disabled" shows only 100 songs always! At the bottom of the Tracks manager window is written "1-100/0" which makes no sense
- Choosing the option "Show All" shows ONLY first 2600 songs but it displays correctly mixed enabled and disabled songs, but there is absolutely no chance to display more
When I enable one song, I see first 2601 songs in "Show All", 2601 in "Enabled" and still only first 100 in "Disabled".
I used the MySQL statement "UPDATE songs SET enabled = 1" and after that - WOW!

There are all songs, but all are enabled, but this is not a goal to enable all...