[BetterRed]

Originally Posted by laji

The other probleme in Calibre by using custom columns is, that a "show metadata" window, what was very informative, when I started to use Calibre, now became an absolutely chaos. It shows all custom columns (and in not reorderable way...)

That is not quite true!

See Tweak - Order of custom column(s) in edit metadata

ID: metadata_edit_custom_column_order

Controls the order that custom columns are listed in edit metadata single and bulk. The columns listed in the tweak are displayed first and in the order provided. Any columns not listed are dislayed after the listed ones, in alphabetical order. Do note that this tweak does not change the size of the edit widgets.

Putting comments widgets in this list may result in some odd widget spacing when using two-column mode.

Enter a comma-separated list of custom field lookup names, as in
metadata_edit_custom_column_order = ['#genre', '#mytags', '#etc']

Apologies DaltonST - but as someone once said "A lie gets halfway around the world before the truth has a chance to get its pants on."